Method and apparatus for processing a wafer

ABSTRACT

A method of a single wafer wet/dry cleaning apparatus comprising: a transfer chamber having a wafer handler contained therein; a first single wafer wet cleaning chamber directly coupled to the transfer chamber; and a first single wafer ashing chamber directly coupled to the transfer chamber.

This is a Division of application Ser. No. 10/229,446 filed Aug. 27,2002 which is a Continuation-in-Part of application Ser. No. 09/945,454filed Aug. 31, 2001.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of semiconductor processingand more specifically to a method and apparatus for atmospheric andsub-atmospheric processing of a single wafer.

2. Discussion of Related Art

In silicon wafer processing, a wafer undergoes a predetermined sequenceand steps to make an electronic circuit. Some steps are carried out atan atmospheric pressure while other steps are carried out at asub-atmospheric pressure. Typically, a wafer undergoes a process step ina process chamber. Process chambers are loaded by a robot. Either asingle robot, or more than one robot, for loading a single processchamber or more than one process chambers together with process chambersis called a tool or platform. Different tools or platforms can containdifferent of similar process chambers. All tools together contain thenecessary process chambers to complete an entire process sequence thatis necessary to fabricate an electronic circuit. Wafers are transportedfrom one tool to another tool in cassettes. In each tool a robot takesthe wafers out of the cassette and loads them separately or in a batchinto a process chamber or multiple process chambers of that particulartool. After processing, the robot returns the wafers to the samecassette or to a different cassette and the entire cassette is thentransported to the next tool in the fab to perform the next processstep.

In a number of instances, it is advantageous to combine severaldifferent process chambers in one tool. In such a tool the robot takesthe wafers out of the wafer cassette and loads them into the firstprocess chamber. After the process is finished in that process chamber,instead of returning the wafer to the cassette the robot then loads thewafer into the next process chamber to perform the next process step.After the next process step, there can be another process step and so onuntil the wafer has undergone all process steps that are available inthat tool. After the last process step of that tool, the wafers are thenfinally returned to their wafer cassette and the cassette transported tothe next tool in the fab. Such a tool with one or more different processchambers are presently referred to as “cluster tools”.

The advantages of a cluster tool include: reduced wafer travelingdistance, reduced footprint, reduced cycle time, and improved yield. Thereduced wafer traveling distance, reduced footprint, and reduced cycletime are a result of the reduced handling of the wafers. The improvedyield is a result of the reduced exposure of the wafer surface to thefab atmosphere. The detrimental affect of the fab atmosphere exposureduring transport from one tool to another is dependent on the particularsequence of process steps. Fab atmosphere exposure can be verydetrimental to electronic circuit yield between certain steps while itmay not affect whatsoever the yield between certain other steps.

The clustering of different process steps in one tool also has somedisadvantages. For example, if one process chamber is inoperable due toa technical failure, the entire tool may not be available and thereforetechnical failure in one process chamber can have detrimental affect onthe availability of the other process chambers. Nevertheless, in certainoccasions, the advantages outlined above of clustering differentsequential process tools in one tool might be higher than thedisadvantage of lower availability or reliability. Therefore, there area number of instances where clustering of different process steps anddifferent process chambers around one or more robots in the single toolis desirable. There are a number of examples where this has been doneand where commercial success is achieved proving the benefits of suchclustering. Most of the existing clustering tools have some processbenefit (i.e., reduced exposure to the fab environment increases theyield).

One example of a cluster tool is a sub-atmospheric cluster tool. In sucha tool different sub-atmospheric process chambers are provided around asub-atmospheric wafer handler or robot. In this case, the clusteringprovides a benefit that the process chambers do not get exposed to theatmosphere and the wafers do not get exposed to the atmosphere whilebeing transferred from one chamber to another chamber. This isespecially useful in the sequence, such as titanium nitride sputtering,aluminum sputtering, titanium nitride sputtering which is generally usedto form metal interconnects of an integrated circuit. Another example ofa cluster tool is an atmospheric process cluster tool. For example, achemical mechanical polishing process chamber can be clustered with acleaning step such that the wafers are transported from the chemicalpolishing process to the cleaning process while the wafers are still ina wet condition. This avoids having to dry the wafers between the twosteps. Drying wafers between the two steps makes it much more difficultto clean the wafers.

Thus, what is desired are novel cluster tool combinations as well ascluster tools which utilizes both atmospheric and sub-atmosphericprocess chambers.

SUMMARY OF THE INVENTION

A method of a single wafer wet/dry cleaning apparatus comprising:

a transfer chamber having a wafer handler contained therein;

a first single wafer wet cleaning chamber directly coupled to thetransfer chamber; and

a first single wafer ashing chamber directly coupled to the transferchamber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overhead illustration of a atmospheric cluster tool havinga single wafer wet cleaning module, a single wafer strip module, and aintegrated process metrology tool each coupled around an atmospherictransfer chamber having a robot contained therein.

FIGS. 2A-2C is an illustration of a single wafer wet clean module inaccordance with an embodiment of the present invention.

FIG. 3 is an illustration of a cross-sectional view of an integratedparticle monitoring tool in accordance with an embodiment of the presentinvention.

FIG. 4 is an illustration of a cross-sectional view of a single waferstripping module in accordance with an embodiment of the presentinvention.

FIG. 5A-5D illustrate a dry stripping and wet cleaning process inaccordance with an embodiment of the present invention.

FIG. 6 is an illustration of a atmospheric/sub-atmospheric process toolfor the etching, stripping, cleaning and monitoring of a wafer inaccordance with an embodiment of the present invention.

FIG. 7 is a block diagram of a review or monitoring tool according to anembodiment of the present invention.

FIGS. 8A and 8B are flowcharts illustrating sequential steps inmonitoring methods according to embodiments of the present invention.

FIG. 9 is a schematic sectional sideview of an etching chamber.

FIGS. 10A-10E illustrate a method of etching conductive features, andthen stripping and cleaning a wafer in accordance with an embodiment ofthe present invention.

FIGS. 11A-11F illustrate a damascene process in accordance with anembodiment of the present invention.

FIG. 12 is an illustration of an atmospheric/sub-atmospheric processtool which can be used to clean, grow a dielectric layer, and deposit asilicon film on a wafer in accordance with an embodiment of the presentinvention.

FIG. 13A illustrate a rapid thermal heating apparatus which can grow adielectric layer in accordance with an embodiment of the presentinvention.

FIG. 13B illustrate the light source placement in the rapid thermalheating apparatus of FIG. 13A.

FIG. 14A shows an illustration of a cross-sectional side view aprocessing chamber comprising of a resistive heater in a “wafer-process”position in accordance with an embodiment of the invention through firstcross-section and a second cross-section each through one-half of thechamber.

FIG. 14B shows an illustration of a similar cross-sectional side view asin FIG. 14A in a wafer separate position.

FIG. 14C shows an illustration of a similar cross-sectional side view asin FIG. 14A in a wafer load position.

FIG. 15A-15E illustrate a method of depositing and forming a dielectricfilm and a gate electrode in accordance with an embodiment of thepresent invention.

FIG. 16A-16C illustrate a method of removing a silicon nitride film inaccordance with an embodiment of the present invention.

FIG. 17A is a perspective view of high k dielectric deposition module ofthe present invention.

FIG. 17B is a cross sectional view of the chamber of high k dielectricdeposition module.

FIG. 17C is a schematic view of a typical remote plasma generator.

FIG. 18A is an overhead illustration of a photolithographic tool inaccordance with the present invention.

FIG. 18B is an overhead illustration of a photolithographic tool inaccordance with an embodiment of the present invention.

FIG. 18C is an overhead illustration of a photolithographic process inaccordance with an embodiment of the present invention.

FIG. 18D is an overhead illustration of a photolithographic apparatus inaccordance with an embodiment of the present invention.

FIG. 19-A-19G illustrates a method of cleaning a wafer, forming aphotoresist film on the wafer and exposing the photoresist film inaccordance with an embodiment of the present invention.

FIG. 20A is an illustration of a computer/controller which can be usedin the tools of the present invention.

FIG. 20B is an illustration of a software program which can be used tocontrol the tools of the present invention.

DETAILED DESCRIPTION

I) Dry/Wet Processing Tool

FIG. 1 illustrates an apparatus or system 100 for the stripping(ashing), wet cleaning and particle monitoring of a wafer during themanufacture of a semiconductor integrated circuit. The cleaningapparatus 100 includes a central transfer chamber 102 having a waferhandling device 104 contained therein. Directly attached to transferchamber 102 is a single wafer wet cleaning module 200, a strip module400, and an integrated process monitoring tool 300, such as anintegrated particle monitor. Wet cleaning module 200, strip module 400,and integrated particle monitor 300 are each connected to transferchamber 102 through a separately closable opening. In an embodiment ofthe present invention, a second wet cleaning module 200B and/or a secondstrip module 400B are also coupled to transfer chamber 102. In anembodiment of the present invention, transfer chamber 102 is maintainedat substantially atmospheric pressure (i.e., atmospheric transferchamber) during operation. In an embodiment of the present invention,the atmospheric transfer chamber 102 can be opened or exposed to theatmosphere of a semiconductor fabrication “clean room” in which it islocated. In such a case, the transfer chamber 102 may contain anoverhead filter, such as a hepafilter to provide a high velocity flow ofclean air or an inert ambient such as N₂, to prevent contaminants fromfinding their way into the atmospheric transfer chamber. In otherembodiments, the atmospheric transfer chamber 102 is a closed system andmay contain its own ambient, of clean air or an inert ambient, such asnitrogen gas (N₂).

Transfer chamber 102 includes a wafer handling robot which can transfera wafer from one module to another. In an embodiment of the presentinvention, the wafer handler is a single robot with two wafer handlingblades 114 and 116 which both rotate about a single axis 119 coupled tothe end of a single arm 120. Robot 104 can be said to be a dual bladesingle arm, single wrist robot. Robot 104 moves on a track 122 along asingle axis in transfer chamber 102.

A system computer 124 is coupled to and controls each wet clean module200, strip module 400 and integrated particle monitoring module 300 aswell as the operation of transfer chamber 102 and robot 104. Computer124 enables the feedback from one module, such as the integratedparticle monitoring module, to be used to control the flow of a waferthrough system 100 and/or to control the process within a differentmodule.

Also coupled to transfer chamber 102 is at least one wafer input/outputmodule 130 or pod for providing wafers to system 100 and for takingwafers away from system 100. In an embodiment of the present invention,the wafer input/output module 106 is a front opening unified pod (FOUP)which is a container having a slideable and sealable door and whichcontains a cassette of between 13-25 horizontally spaced wafers.Transfer chamber 102 contains a sealable access door 110 which slidesvertically up and down to enable access into and out of transfer chamber102. In an embodiment of the present invention, apparatus 100 includestwo FOUP's, 106 and 108 one for providing wafers into system 100 and onefor removing completed or processed wafers from system 100. However, awafer can be inputted and outputted from the same FOUP, if desired. Asecond access door 112 is provided to accommodate a second FOUP 108.Each access door can be attached to the counter part door on each FOUPso that when the transfer chamber access door 110 and 112 slides open,it opens the door of the FOUP to provide access for the robot into theFOUP. The FOUP's can be manually inserted onto apparatus 100 or a waferstocking system 114, such as a Stocker, having multiple FOUP's in a railsystem can be used to load and remove FOUP's from apparatus 100.

A) Single Wafer Wet Cleaning Module

An example of a single wafer cleaning module 200 which can be used aswet cleaning module 200 and 200B (if used) is illustrated in FIGS.2A-2C. FIGS. 2A-2C illustrate a single wafer cleaning apparatus 200which utilizes acoustic or sonic waves to enhance a cleaning. Singlewafer cleaning apparatus 200 shown in FIG. 2A includes a plate 202 witha plurality of acoustic or sonic transducers 204 located thereon. Plate202 maybe made of aluminum but can be formed of other materials such asbut not limited to stainless steel and sapphire. The plate is maybecoated with a corrosion resistant fluoropolymer such as Halar or PFA.The transducers 204 are attached to the bottom surface of plate 202 byan epoxy 206. In an embodiment of the present invention the transducers204 cover substantially the entire bottom surface of plate 202 as shownin FIG. 2 b and cover at least 80% of plate 202. The transducers 204generate sonic waves in the frequency range e.g. between 400 kHz and 8MHz. In an embodiment of the present invention the transducers 204 arepiezoelectric devices. The transducers 204 create acoustic or sonicwaves in a direction perpendicular to the surface of wafer 208.

A substrate or wafer 208 is held at distance of about 3 mm above the topsurface of plate 202. The wafer 208 is clamped by a plurality of clamps210 face up to a wafer support 212 which can rotate wafer 208 about itscentral axis. The wafer support can rotate or spin wafer 208 about itscentral axis at a rate between 0-6000 rpm. In apparatus 200 only wafersupport 212 and wafer 208 are rotated during use whereas plate 202remains in a fixed position. Additionally, in apparatus 200 wafer 208 isplaced face up wherein the side of the wafer with patterns or featuressuch as transistors faces towards a nozzle 214 for spraying cleaningchemicals or water thereon and the backside of the wafer faces plate202. Additionally, as shown in FIG. 2C the transducer covered plate 202has a substantially same shape as wafer 208 and covers the entiresurface area of wafer 208. Apparatus 200 can include a sealable chamber201 in which nozzle 214, wafer 208, and plate 202 are located as shownin FIG. 2A.

In an embodiment of the present invention, during use, DI water (DI—H₂O)is fed through a feed through channel 216 of plate 202 and fills the gapbetween the backside of wafer 208 and plate 202 to provide a waterfilled gap 218 through which acoustic waves generated by transducers 204can travel to substrate 208. In an embodiment of the present inventionDI water fed between wafer 208 and plate 202 is degassed so thatcavitation is reduced in the DI water filled gap 218 where the acousticwaves are strongest thereby reducing potential damage to wafer 208. Inan alternative embodiment of the present invention, instead of flowingDI—H₂O through channel 216 during use, cleaning chemicals, such as thecleaning solution of the present invention can be fed through channel216 to fill gap 218 to provide chemical cleaning of the backside ofwafer 208, if desired.

Additionally during use, cleaning chemicals and rinsing water such asDI—H₂O are fed through a nozzle 214 to generate a spray 220 of dropletswhich form a liquid coating 222 on the top surface of wafer 208 whilewafer 208 is spun. In the present embodiment the liquid coating 222 canbe as thin as 100 micron. In the present embodiment tanks 224 containingcleaning chemicals such as diluted HF, de-ionized water (DI—H₂O), andthe cleaning solution of the present embodiment are coupled to conduit226 which feeds nozzle 214. In an embodiment of the present inventionthe diameter of conduit 226 has a reduced cross-sectional area or a“Venturi” 228 in a line before spray nozzle 214 at which point a gassuch as H₂ is dissolved in the cleaning solution as it travels to nozzle214. “Venturi” 228 enables a gas to be dissolved into a fluid flow atgas pressure less than the pressure of the liquid flowing throughconduit 226. The Venturi 228 creates under pressure locally because ofthe increase in flow rate at the Venturi.

B) Integrated Particle Monitor

In an embodiment of the present invention, the integrated processmonitoring tool 110 is an integrated particle monitor (IPM) 300 such asshown in FIG. 3. An example of a suitable integrated particle monitor(IPM) 300 is the IPM tool manufactured by Applied Materials of SantaClara, Calif. According to one embodiment of the present invention, theintegrated particle monitor 300 includes a rotatable wafer support 302for holding a wafer 301 and for rotating a wafer on its central axis. Alaser source 304 shines a laser beam 306 on wafer 301 and the locationof the reflected beam 308 is detected by one or more of a plurality ofdetectors 310. Detection of the reflected beam 308 by one or more adetector 310 can be used as an indication of the presence of theparticle at the location. The detectors can take the form of “brightfield” detectors, “dark field” detectors or combination of “brightfield” and “dark field” detectors. The laser beam 306 can be scannedacross the radius of the wafer while the wafer is rotated in order tomonitor the entire wafer surface for particles. Computer 124 along withdata processing software can be used to generate a defect map of theentire wafer surface. Software can be used to analyze the particle map,by for example, comparing to a blank wafer or by comparing the particlemap of one die on the wafer to other dies on the same or differentwafer. The software can be used to classify defects as particles ormicroscratches. The data from the integrated particle monitoring tool300 can be used to determine when downstream chambers have excurted fromtheir process base lines (i.e., chamber excursions). Similarly, theparticle maps can be sent to upstream chambers or modules in order toalter or optimize or change the upstream process in view of the defectmap.

C) Strip or Dry Cleaning Module

A strip or dry cleaning module 400 in accordance with an embodiment isillustrated in FIG. 4. In the cleaning chamber 400 of the typeillustrated in FIG. 4, an energized process gas comprising cleaning gasis provided to clean the substrate 480 held on the support 410 in aprocess zone 415. The support 410 supports the substrate 480 in theprocess zone 415 and may optionally comprise an electrostatic chuck 412.Within or below the support 410, a heat source, such as infrared lamps420, can be used to heat the substrate 430. The process gas comprisingcleaning gas may be introduced through a gas distributor 422 into aremote plasma generation zone 425 in a remote chamber 430. By “remote”it is meant that the center of the remote chamber 430 is at a fixedupstream distance from the center of a process zone 415 in the cleaningchamber 108. In the remote chamber 430, the cleaning gas is activated bycoupling microwave or RF energy into the remote chamber 430, to energizethe cleaning gas and cause ionization or dissociation of the cleaninggas components, prior to its introduction through a diffuser 435, suchas a showerhead diffuser, into the process zone 415. Alternatively, theprocess gas may be energized in the process zone 415. Spent cleaning gasand residue may be exhausted from the cleaning chamber 108 through anexhaust system 440 capable of achieving a low pressure in the cleaningchamber. A throttle valve 425 in the exhaust 440 is used for maintaininga chamber pressure from about 150 mTorr to about 3000 mTorr.

In the version illustrated in FIG. 4, the remote chamber 430 comprises atube shaped cavity containing at least a portion of the remote plasmazone 425. Flow of cleaning gas into the remote chamber 430 is adjustedby a mass flow controller or gas valve 450. The remote chamber 430 maycomprise wall made of a dielectric material such as quartz, aluminumoxide, or monocrystalline sapphire that is substantially transparent tomicrowave and is non-reactive to the cleaning gas. A microwave generator455 is used to couple microwave radiation to the remote plasma zone 425of the remote chamber 430. A suitable microwave generation 455 is an“ASTEX” Microwave Plasma Generator commercially available from AppliedScience & Technology, Inc., Woburn, Mass. The microwave generatorassembly 455 may comprise a microwave applicator 460, a microwave tuningassembly 465, and a magnetron microwave generator 470. The microwavegenerator may be operated at a power level of about 200 to about 3000Watts, and at a frequency of about 800 MHz to about 3000 MHz. In oneversion, the remote plasma zone 425 is sufficiently distant from theprocess zone 415 to allow recombination of some of the dissociated orionized gaseous chemical species. The resultant reduced concentration offree electrons and charged species in the activated cleaning gasminimizes charge-up damage to the active devices on the substrate 480,and provides better control of the chemical reactivity of the activatedgas formed in the remote plasma zone 425. In one version, the center ofthe remote plasma zone 425 is maintained at a distance of at least about50 cm from the center of the process zone 415.

A cleaning process may be performed in the cleaning chamber 400 byexposing the substrate 480 to energized process gas comprising cleaninggas to, for example, remove remnant resist and/or to remove orinactivate etchant residue remaining on the substrate after thesubstrate is etched. Remnant resist may be removed from the substrate480 in a stripping (or ashing) process by exposing the substrate 480 toenergized process gas comprising stripping gas. Stripping gas maycomprise, for example, one or more of O₂, N₂, H₂, H₂O, NH₃, CF₄, C₂F₆,CHF₃, C₃H₂F₆, C₂H₄F₂, or CH₃F.

Method of Operating Wet/Dry Cleaning Tool 100

Wet/dry cleaning tool 100 is ideal for use in removing a photoresistlayer from a wafer as shown in FIGS. 5A-5D. In an embodiment of thepresent invention, a patterned photoresist layer 502 is removed from awafer 500 after an ion-implantation step 504. The patterned photoresistlayer as shown in FIG. 5 a, forms a mask which is used to mask anion-implantation step which can be used to form doped regions in amonocrystalline silicon substrate 508, such as wells, source/drainregions, channel doping, and other well known doped regions used tofabricate a semiconductor integrated circuit. According to an embodimentof the present invention, a cassette or FOUP of wafers 500 having aphotoresist mask 502 thereon, are placed in a docking station inapparatus 100. An access door 110 in docking station 131 slides down andpulls down the door to FOUP 130. Robot 104 removes a wafer 500 from FOUP130 and places the wafer into dry clean chamber 400. Clean chamber 108is then sealed and pumped down to a pressure of between 150 mTorr to3000 mTorr.

A cleaning process is then performed in the cleaning chamber 400 byexposing the wafer 500 to energized process gas comprising cleaning gasto, for example, remove photoresist mask 502 and/or to remove orinactivate implant residue 512 remaining on the substrate after thesubstrate is etched. Remnant resist 502 may be removed from thesubstrate in a stripping (or ashing) process by exposing the substrateto energized process gas comprising stripping gas. Stripping gas maycomprise, for example, one or more of O₂, N₂, H₂, H₂O, NH₃, CF₄, C₂F₆,CHF₃, C₃H₂F₆, C₂H₄F₂, or CH₃F. In one version, a suitable stripping gasfor stripping polymeric resist material comprises (i) oxygen, andoptionally (ii) an oxygen activating gas or vapor, such as water vapor,nitrogen gas, or fluorocarbon gas, the fluorocarbon gases including anyof those listed above. The oxygen activating gas increases theconcentration of oxygen radicals in the stripping gas. The stripping gascomposition may comprise oxygen and nitrogen in a volumetric flow ratioof about 6:1 to about 200:1, and more likely from about 10:1 to about12:1. For a 5-liter process chamber 108, a suitable gas flow ratecomprises 3000 to 3500 sccm of O₂ and 300 sccm of N₂. In one version, astripping gas comprises about 35000 sccm O₂, about 200 sccm N₂ andoptionally about 300 sccm H₂O, that is energized at a power level ofabout 1400 watts and introduced into the cleaning chamber 108 at apressure of about 2 Torr for about 15 seconds. In one version, the watervapor content in the stripping gas should be less than about 20% byvolume of the combined oxygen and nitrogen gas content to provideadequate stripping rates. A suitable ratio of the volumetric water vaporflow V_(H2O) to the combined volumetric flow of oxygen and nitrogen(V_(O2)+V_(N2)) is from about 1:4 to about 1:40, and more likely about1:10. When the remnant resist comprises oxide hard mask, suitablestripping gases are gases capable of stripping oxide, such as halogencontaining gases, including CF₄, C₂F₆, CHF₃, C₃H₂F₆, C₂H₄F₂, and HF. Thesubstrate 500 may be exposed to the stripping gas for a period of timeof from about 10 seconds to about 1000 seconds, and more likely forabout 45 seconds. A single stripping step may be performed or multiplestripping steps may be performed, as discussed in U.S. Pat. No.5,545,289, which is incorporated herein by reference in its entirety.After stripping or ashing in chamber 400, wafer 500 may still containphotoresist mask residue and/or implant residue 512 as shown in FIG. 5B.

In one version, the substrate may be heated during the stripping and/orthe passivation processes. For example, when cleaning the substrate 500in a cleaning chamber 400, such as the cleaning chamber of FIG. 4, thelamps 420 may be used to heat the substrate to a temperature of at leastabout 150° C., and more specifically to a temperature of at least about250° C. Heating the substrate 500 improves the remnant resist removalrate and may also improve the removal rate of some etchant residue, suchas Cl in the sidewall deposits 80, because the Cl can more readilydiffuse out of the sidewall deposits. The elevated temperature alsoenhances the surface oxidation, when O₂ containing strip density isused, of the etched metal, making them less susceptible to corrosion.

In one embodiment of the present invention, the wafer is thentransferred to the wet cleaning chamber 200 and is exposed to a lightclean consisting of only a Di water rinse. In another embodiment of thepresent invention, the wafer is exposed to a Di water rinse which hasbeen ozonated. The ozonated water oxidizes carbon left over from theashing and insures its removal. In yet another embodiment of the presentinvention, the wafer is exposed to an ozonated water rinse and tocleaning chemicals comprising NH₄OH, H₂O₂, a surfactant and a chelatingagent. In yet another embodiment of the present invention, the wafer isexposed to an ozonated Di water then HF then cleaning solutionscomprising NH₄OH, H₂O₂, a surfactant and a chelating agent. In yetanother embodiment of the present invention, the wafers are exposed to amixture comprising sulfuric acid (H₂SO₄) and hydrogen peroxide (H₂O₂)and then exposed to a water rinse and dry. In yet another embodiment ofthe present invention, the wafers are exposed to standard RCA cleaningsolutions of SC1 and SC2 and then exposed to a water rinse and dry.While the wafers are being cleaned megasonic energy can be applied tothe wafer to enhance the cleaning. In an embodiment of the presentinvention, megasonics is applied to the entire backside of the waferwhile cleaning. Not only can the cleaning solution being applied to thedevice side of the wafer (frontside of the wafer) but can also beapplied to the backside of the wafer, if desired.

After the wafer 500 has been sufficiently cleaned, as shown in FIG. 5C,the door to the wet cleaning module 200 opens and the robot 104 removesthe wafer from the wet module 200. If process metrology of the wafer 500is desired, the door to the metrology tool 300 is opened and the robot104 transfers the wafer into the process metrology tool 300. The door tothe integrated particle monitor 300 is then closed and the wafer 500scanned, as shown in FIG. 5D, to check for defects, such as scratchesand particles. Computer/controller 124 can generate a defect map of thedefects across the surface of wafer 500. Computer/controller 124 anddata process software can determine whether or not the wafer has beensufficiently cleaned by the stripping chamber 400 and the wet cleaningchambers 200 and can be used to determine which type of defects haveoccurred. Depending upon the results of the metrology scan, the wafercan be removed from the integrated particle monitor tool 110 and can beeither: (i) transferred back to the wet cleaning module 200 for furtherwet cleaning, (ii) transferred back to the dry clean module 400 for morestripping, (iii) can be transferred back to both the dry clean module400 and the wet cleaning module 200 for further stripping and cleaningor (iv) can be transferred back to the FOUP. The amount of and/or typeof clean or stripping necessary can be determined by the informationreceived from the integrated particle monitor tool 300. If the wafer hasbeen sufficiently stripped and cleaned, the wafer can be removed fromthe integrated particle monitor by robot 104 and moved through thetransfer chamber 102 whereby the access door as well as the door to thewafer cassette or FOUP which is to receive the wafer is opened and thewafer placed therein. The wafer can be placed into the same FOUP 130 inwhich the wafer started or can be placed in a different FOUP 132, ifdesired.

In an embodiment of the present invention, the process time in eachmodule and the number of each module are chosen so that the wafer flowis balanced for optimum use of each module. For example, in anembodiment of the present invention, the process time used to strip awafer in cleaning module 400 is chosen to be substantially similar tothe process time used to wet clean a wafer in wet clean module 200 andis about twice as long as the time necessary to check a wafer fordefects in module 300. Accordingly, apparatus 100 includes two wet cleanmodules 200 and 200B, and two strip modules 400 and 400B, and a singlemetrology tool 300. By providing two wet cleaning tools 200 and 200B andtwo ashing tools 400 and 400B and a single metrology tool 300, no moduleis left idle. For example, if the wet cleaning time is chosen to be twominutes then the stripping time is chosen to be two minutes, and themetrology tool takes one minute then the wafer throughput of the modulesis balanced. By providing more modules for the processes which takelonger (e.g., to clean and strip) faster processing modules (e.g.,metrology) do not sit idle while waiting for a wafer to completecleaning or stripping. In such a process, a wafer completes processing(strips, cleans, and metrology) every 60 seconds (apparatus 100 has awafer through put of 60 seconds) as opposed to every 120 seconds if thetool was unbalanced and only had one wet clean or one strip module inapparatus 100. Preventing idle time of the modules contained inapparatus 100 directly increases wafer through put and reduces a cost ofownership of the apparatus.

II) Atmospheric and Sub-Atmospheric Process Tool

According to another embodiment of the present invention, a process toolor apparatus having both atmospheric and sub-atmospheric processchambers or modules is provided. According to this embodiment of thepresent invention, the process tool includes an atmospheric platformcoupled via a load lock to a sub-atmospheric platform. (A platform is atransfer chamber having a robot contained therein and process modulesattached thereto). Attached to the sub-atmospheric transfer chamber aresub-atmospheric process modules, such as but not limited to etchmodules, deposition chambers such as CVD chambers and sputter chambers,oxidation chambers, and anneal chambers. Attached to the atmospherictransfer chamber are atmospheric process modules, such as wet cleaningtools, ashing (stripping) tools, and metrology tools. The ashing(stripping) chambers can be connected to either the atmospheric platformor the sub-atmospheric platform or both. The atmospheric/sub-atmospherictool utilizes a single wafer load lock and generally two single waferload locks coupled between the atmospheric and sub-atmospheric platformsto enable transfer of wafer between the atmospheric and sub-atmospherictransfer chambers. In an embodiment of the present invention, wafersenter the tool through the atmospheric transfer chamber and also exitthe tool through the atmospheric transfer chamber. Some of the benefitsof the atmospheric and sub-atmospheric process tool include the factthat Queue time between two process steps can be reduced and madeconsistent and independent of Queing or material logistic issues.Additionally, the growth of silicon dioxide on silicon is reduced due toreduced exposure (in time) to air. Particle and contamination controlcan be improved through reduced exposure to the fab environment. Anatmospheric/sub-atmospheric process tool can provide processing of awafer in reduced cycle times and also provides a reduced footprint ofthe tool. Additionally, an atmospheric/sub-atmospheric process tool canreduce corrosion of, for example metal lines, through reduced exposureto air. Additionally, the amount of distance a wafer must travel is alsoreduced thereby improving wafer throughput and contamination control.

Etch/Strip Clean Process Tool

An example of an atmospheric/sub-atmospheric process apparatus 600 inaccordance with the present invention is illustrated in FIG. 6. Shown inFIG. 6 is a process tool or system 600 which can be used to etchfeatures, such as metal or polysilicon lines, or opening in dielectriclayers or silicon substrates and can be used to strip or clean thephotoresist layer used to pattern the features. Etch/strip process tool600 includes an atmospheric platform 602 and a sub-atmospheric platform604. The sub-atmospheric platform 604 and the atmospheric platform 602are coupled together by a single wafer load lock 606 and generally bytwo single wafer load locks 606 and 608. Atmospheric platform 602includes a central atmospheric transfer chamber 610 having a waferhandling device 612, such as a robot contained therein. Directlyattached to atmospheric transfer chamber 610 is a single wafer wetcleaning module 200 and an integrated particle monitor 300 and acritical dimension (CD) measuring tool 700. A strip or dry clean module400 can also be attached to atmospheric transfer chamber 610, ifdesired. Wet cleaning module 200, strip module 400, integrated particlemonitor 300, and critical dimension measuring tool 700 are eachconnected to transfer chamber 610 through a separately closable andsealable opening, such as a slit valve. Transfer chamber 610 ismaintained at substantially atmospheric pressure during operation. In anembodiment of the present invention, the atmospheric transfer chamber610 can be opened or exposed to the atmosphere of a semiconductorfabrication “clean room” in which it is located. In such a case, thetransfer chamber 610 may contain an overhead filter, such as ahepafilter to provide a high velocity flow of clean air or an inertambient such as N₂, to prevent contaminants from finding their way intothe atmospheric transfer chamber. In other embodiments, the atmospherictransfer chamber 610 is a closed system and may contain its own ambient,of clean air or an inert ambient, such as nitrogen gas (N₂).

Atmospheric transfer chamber 610 includes a wafer handling robot 612which can transfer a wafer from one module to another module inatmospheric process tool 602. In an embodiment of the present invention,the wafer handler 612 is a dual blade, single arm, single wrist robot.The handling blades both rotate about a single axis coupled to the endof a single arm as described above.

Also coupled to atmospheric transfer chamber 610 is at least one waferinput/output module 620 or pod for providing and taking wafer to andfrom system 600. In an embodiment of the present invention, the waferinput/output module is a front opening unified pod (FOUP) which is acontainer having a sealable door and which contains a cassette forbetween 13-25 horizontally spaced wafers. In an embodiment of thepresent invention, apparatus 600 includes two FOUPs 622 and 624, one forproviding wafers into system 600 and one for removing completed orprocessed wafers from system 600. Atmospheric transfer chamber 610contains a sealable access door 621 for allowing wafers to betransferred into and out of atmospheric transfer chamber 610. There isan access door 621 for each FOUP, and each assess door is attached to acounter part door on each FOUP so that when transfer chamber access door621 slides open, it opens the door to the associated FOUP to provideaccess for the robot 612 into the FOUP.

Coupled to the opposite sides of atmospheric transfer chamber 610 thenFOUP 622 and 624 is a single wafer load lock 606 and optionally secondsingle wafer load lock 608. Single wafer load locks 606 and 608 enable awafer to be transferred from the atmospheric conditions in transferchamber 610 to the sub-atmospheric transfer chamber 630 of platform 604and allows wafers to be transferred from the sub-atmospheric transferchamber 630 to the atmospheric transfer chamber 610. A sealable door 605is located between atmospheric transfer chamber 610 and load lock 606and a sealable door 607 is located between sub-atmospheric transferchamber 630 and load lock 606. Similarly, a sealable door 609 is locatedbetween atmospheric transfer chamber 610 and load lock 608 and asealable door 611 is located between sub-atmospheric transfer chamber630 and load lock 608. Coupled to each load locks 606 and 608 is avacuum source which enables the pressure inside load locks 606 and 608to be independently lowered. Additionally, also coupled to each loadlock 606 and 608 is a gas inlet for providing, for example, air or aninert gas, such as N₂, into a load lock to enable the pressure withinthe load lock to be raised. In this way, the pressure within the loadlocks 606 and 608 can be matched to either the pressure withinatmospheric transfer chamber 610 or the pressure within sub-atmospherictransfer chamber 630.

Attached to the opposite ends of the single wafer load locks 606 and 608is sub-atmospheric transfer 630 having a wafer handling device 632, suchas a robot contained therein. Sub-atmospheric transfer chamber 630 issaid to be a sub-atmospheric transfer chamber because transfer chamber630 is held at a pressure less than atmospheric pressure and generallybetween 10⁻⁶-10 Torr while in operation and passing wafers to thevarious sub-atmospheric process modules coupled thereto. Directlyattached to sub-atmospheric transfer chamber 630 is a single wafer stripmodule 400B and an etch module 900 optionally. Strip module 400B andetch module 900 are connected to sub-atmospheric transfer chamber 630through separately closable openings. In an embodiment of the presentinvention, a second strip module 400C and a second etch 900B are alsocoupled to sub-atmospheric transfer chamber 630. Although, load locks606 and 608 are ideally low volume single wafer load locks to enablefast wafer transfers between the atmospheric transfer chamber and thesub-atmospheric transfer chamber, load locks 606 and 608, however, canbe larger multiple wafer load locks which can hold multiple wafers at asingle time, if desired.

It is to be noted that the ashing or stripping processes which occur instrip module 400 (as well as modules 400B and 400C) typically occur atsub-atmospheric pressures. Accordingly, it is advisable to place thestripping modules necessary for the process onto sub-atmospherictransfer chamber because it simplifies and reduces the pumpingrequirements in the stripping module. There are, however, times when itmaybe beneficial or necessary to include a stripping module 400 onatmospheric transfer chamber 610. For example, if all module location onthe sub-atmospheric transfer chamber are occupied by other modules onecan place the stripping module on the atmospheric transfer chamber 610.Additionally, some integrated processes may require excessive wafertransfers between sub-atmospheric chamber 630 and atmospheric transferchamber 610 resulting in the over use of load lock 608 and 606 andpossible bottle neck at these locations. For example, in the case when awafer is given a quick wet clean to remove sidewall residue prior toashing or stripping, it may be desirable to provide a strip module 400on the atmospheric transfer chamber 610 so that the wafer does not needto travel back through the load locks and into the sub-atmospherictransfer chamber to the stripping module after wet cleaning in a wetmodule 200 coupled to the atmospheric transfer chamber. As such,although stripping module(s) 400 is ideally coupled to sub-atmospherictransfer chamber 630, a strip module 400 can be included on atmospherictransfer chamber 610 or on both atmospheric transfer chamber 610 and onsub-atmospheric transfer chamber 630, if desired.

Apparatus 600 also includes a system computer 124 which is coupled toand controls each module coupled to the atmospheric transfer chamber610, controls each sub-atmospheric module coupled to sub-atmospherictransfer chamber 630, controls load locks 606 and 608 as well as theoperation of robots 612 and 632. Computer 124 enables the feedback fromone module to be used to control the flow of a wafer through system 600and/or to control the processes or operation of the other modules.

Critical Dimension (CD) Monitor

FIG. 7 illustrates a critical dimension monitoring tool or a “metrology”tool 700 which can be used to measure, for example, the width ofphotoresist feature formed on an incoming wafer.

The present invention can be implemented with a metrology tool 700, suchas shown in FIG. 7. Metrology tool 700 includes an imager 710 and acomputer/controller 124 to perform the analysis disclosed hereinelectronically. Computer/Controller 124 typically includes a processmonitor 730 for displaying results of the analyses of processor 720.Processor 720 can be in communication with a memory device 740, such asa semiconductor memory, and a computer software-implemented databasesystem 750 known as a “manufacturing execution system” (MES)conventionally used for storage of process information. Processor 720 isalso in communication with a photo cell 760 and etcher 900. In anembodiment of the present invention, the imager 710 can be an optical CDtool (OCD), such as the Nano OCD 9000 available from Nanometrics ofMilpitas, Calif., or an optical imager as disclosed in U.S. Pat. No.5,963,329. Optical imager 710 can utilize scatterometry or reflectometrytechniques. The use of scatterometry for inspection tools is disclosedin Raymond “Angle-resolved scattermetry for semiconductormanufacturing”, Microlithography World, Winter 2000. The use ofreflectometry for inspection is taught in Lee, “Analysis ofReflectometry and Ellipsometry Data from Patterned Structures”,Characterization and Metrology for ULSI Technology: 1998 InternationalConference, The American Institute of Physics 1998.

Optical imager 710 can directly measure CD and profile of certainpatterns on photoresist layer, such as trenches and the like usingconvention optical inspection techniques. For example, a rigorouscoupled wave analysis (RCWA) can be performed, wherein a CDcorresponding to a given waveform is derived by calculation, such as bya processor in the optical inspection tool. RCWA is discussed inChateau, “Algorithm for the rigorous couple-wave analysis of gratingdiffraction”, Journal of the Optical Society of America, Vol. 11, No. 4(April 1994) and Moharam, “Stable implementation of the rigorouscouple-wave analysis for surface-relief gratings: enhanced transmittancematrix approach”, Journal of the Optical Society of America, Vol. 12,No. 3 (May 1995).

In an embodiment imager 710 can be a CD SEM, such as the Versa SEM™available from Applied Materials of Santa Clara, Calif.

FIG. 8A is a flow chart illustrating the major steps of process controlaccording to an embodiment of the present invention, implemented inconjunction with inspecting a feature (hereinafter called a “targetfeature”) such as an etch mask formed on a semiconductor wafer W atphoto cell 760. At step 810, the reference library is created, includingreference CDs and waveforms in the form of SEM or OCD waveforms, andstored locally in inspection tool 700 or in MES 750. The steppersettings associated with each of the reference waveforms and theappropriate etch recipes are stored along with the waveforms. Profileimages can also be stored, if desired by the user. The reference libraryis created only once for each layer to be inspected, such as when aseries of process steps, such as photo cell 760, creates a “criticallayer” that the user determines must be inspected. The golden waveform;i.e., the waveform associated with the reference feature exhibitingoptimal CD and/or other characteristics, is selected at step 820.

Computer/Controller 124 typically includes a processor 720, such as amicroprocessor, for processing information, and a monitor 730 fordisplaying or outputting information, and a input device 732, such as akeyboard or touch screen, and a memory, such as a DRAM for steadyinformation.

Wafer W, having features with unknown CD and other characteristics, isbrought to imager 710 from photo cell 760, the target feature is imagedby imager 710 at step 830, and its waveform is stored as a targetwaveform. At step 840, the target waveform is compared to the storedgolden waveform. If the target waveform and golden waveform match withinpredetermined limits, the CD of the target feature is reported to theuser, as by a display on monitor 730, along with a “matching score”indicating the amount of deviation of the target waveform from thegolden waveform (see step 841). The results (i.e., the data) from theinspection are then sent to MES 750, and the wafer W is sent to etcher900 for further processing.

If the target waveform does not match the golden waveform, the targetwaveform is compared to each of the reference waveforms in the libraryto identify the reference waveform most closely matching the targetwaveform (see step 850). The reported stepper settings are compared withthose associated with the golden waveform at step 860 to determine thedifferent dEdF between the settings which produced the golden waveformand those which produce the target waveform; e.g., determine thedifference between the focus setting associated with the golden waveformand the focus setting associated with the target waveform, and determinethe difference between the exposure setting associated with the goldenwaveform and the exposure setting associated with the target waveform.This information is then sent to photo cell 760, where it is used tocorrect the stepper settings to minimize “drift” in the stepper, whichwould cause CD variations in subsequently processed wafers, byindicating the amount of adjustment to the stepper that is required, aswell as which particular adjustments (i.e., focus, exposure, or both)should be made.

Next, dE and dF are compared to predetermined threshold values at step870. If dE and dF are not greater than the predetermined thresholdvalues, the CD and matching score of the target feature are reported atstep 871, the data from the inspection is then sent to MES 750, andwafer W is sent to etcher 900. On the other hand, if dE and dF aregreater than the predetermined threshold values, the CD and matchingscore of the target feature is reported at step 880, along with dE anddF and the associated etch recipe, which is sent to etcher 900 to adjust(or “update”) the etch recipe to correct the CD deviation of thefinished features on wafer W. The etch recipes can typically adjust theCD within a range of about 100% or less.

The feedback and feed-forward of steps 860 and 880 can be done manuallyor automatically. In “manual mode”, the user takes the reported processcorrection information and implements it manually at photo cell 760and/or etcher 900. This allows expert input from the user to decide theneed for process adjustment. In “automatic mode”, the process correctioninformation is automatically fed to the stepper in photo cell 760 or toetcher 900 to effect the correction through recipe updating. This modecan be implemented by a software interface allowing communicationbetween processor 720 and etcher 900, and between processor 720 andphoto cell 760. The predetermined threshold test of step 870 can be usedas a sensitivity filter to determine if updating is necessary. Theautomatic mode is advantageous because it enables quick feedback andconsistency.

The above embodiment of the present invention has been describedrelative to a “golden waveform” technique. However, it should berealized by any SEM CD measurement technique capable of correlating anFEM cell (or dF) to an etch recipe and to feature profile and/orcross-section can be used to implement the present invention. An exampleof such a technique is discussed in “An Inverse Scattering Approach toSEM Line Width Measurements”, Mark P. Davidson and Andras E. Vladar,Proceedings of SPIE, Vol. 3677 (1999). In this technique, SEM waveformsare matched to a library of Monte Carlo simulations to predict thesidewall shape and dimensions of a feature (i.e., the feature profile).

Typically, the present methodology is carried out after a lot of wafers,such as about 25 wafer, is processed by photo cell 760. A number ofwafers W from the lot are selected to be inspected, according to theuser's preference. For example, when manufacturing microprocessors, 1-3wafers are typically selected for inspection; however, whenmanufacturing memory devices such as DRAMs, only one wafer is typicallyinspected per lot. A number of sites on each selected wafer W areusually inspected by the present methodology (i.e., to be targetfeatures at step 830), such as about 9-17 sites per wafer W. If an OCDis used, each wafer maybe inspected.

To determine the etch recipe to be implemented at step 880 when a numberof target features from one or more wafers W in a lot are inspected, theCDs of all the target features of the lot can be averaged, and the etchrecipe associated with the average CD used to adjust the etch processingof the lot. To determine the stepper focus and exposure information(dEdF) fed back to photo cell 760 at step 860 to adjust thephotolithographic processing of following lots when a number of targetfeatures in a lot are inspected, the user can employ previously gatheredprocess information to decide which sites on selected wafers W toinspect, and then decide which inspected feature's information to use toadjust photo cell 760.

This is illustrated in FIG. 8B, which is a flow chart of an embodimentof the invention. At step 890, the user maps field to field CDvariations across a number of wafers prior to inspection using thepresent methodology. This is a standard process control techniquepracticed by virtually all wafer fabricators. It indicates which areasof the wafer typically have small CD variations from the design value,and which areas of the wafer typically have a large CD variation. Forexample, some wafer processing equipment (e.g., photo cell 760) produceswafer having a small CD variation in the center of the wafer and largerCD variations at the periphery. Other equipment produces wafers havinglarge CD variations near the corner of the wafer and small CD variationsin a band surrounding the center. After mapping the CD variations, theuser identifies, at step 891, an area or areas of the wafers thatexhibit the worst CD variation.

Next, the user selects a threshold CD variation representing thesmallest CD deviation the user wishes to correct (see step 892). Targetfeatures are then inspected at step 893 using the inventive methodology(e.g., steps 830 et seq. described above). Target features are selectedsuch that fields in the worst part of the wafer, identified at step 891,are represented. If the field to field variation of the inspectedfeatures is smaller than the predetermined threshold (see step 894),dEdF associated with any one of the target features can be fed back tophoto cell 760 for use in adjusting the processing of subsequent lots(step 895), since they are relatively close to each other. On the otherhand, if the field to field variation of the inspected features islarger than the threshold value selected in step 892, dEdF associatedwith an inspected feature from the predetermined worst site from step891 is fed back to photo cell 760 (see step 896). Thus, the worst CDvariation is corrected in subsequent lots.

At step 897, the CDs of the inspected features are averaged, and at step898, the etch recipe associated with the average CD is fed forward toetcher 900 to adjust (or “update”) the etch recipe to correct the CDdeviation of the features on the wafers in the inspected lot. Thus, thisembodiment of the present invention allows the user to employinformation, such as field to field CD variation maps, that they gatheras a matter of course independently of implementing the presentinvention, to reduce lot to lot variation with minimal added cost andinspection time.

Etch Module

An example of an etch module 900 which can be used in accordance withthe present invention, is illustrated in FIG. 9. FIG. 9 illustrates anetch process module such as for example, a DPS type Metal Etch Centurachamber, schematically illustrated in FIG. 9 and from Applied Materials,Inc. in Santa Clara, Calif. The particular embodiment of the etch module900 shown herein is provided only to illustrate the invention, andshould not be used to limit the scope of the invention. Etch module 900includes a chamber 910. A support 940 is potential within a process zone945 in the chamber 910. A substrate 930 may be positioned on the support940 by the robotic arm. The substrate 930 may be held in place duringthe etching process using a mechanical or electrostatic chuck 950 withgrooves 955 in which a coolant gas, such as helium, is held to controlthe temperature of the substrate 930.

During processing of the substrate, the chamber 910 may be maintained ata low pressure and process gas may be introduced into the chamber 110through a gas supply 960 having a gas source 962 and gas inlets 964peripherally disposed about the substrate 930. Alternatively, ashowerhead gas distributor (not shown) may be positioned above thesubstrate 930. The process gas may be energized by a gas energizer thatcouples an energetic electromagnetic field into the process zone 945,such as an inductive, capacitive, or microwave field. In the versionshown in FIG. 9, an inductor coil 965 adjacent to the process chamber910 forms an inductive electric field in the chamber 910 when powered bya coil power supply 970 operating using, for example, an RF voltage at asource power level that may be from about 200 Watts to about 2000 Watts.Alternatively or additionally, a capacitive electric field may be formedin the chamber 910. At least a portion of the support 940 may beelectrically conductive to serve as a cathode electrode 975. The cathodeelectrode 975, in conjunction with sidewalls of the chamber 910 whichmay be electrically grounded to serve as an anode electrode 980, formprocess electrodes in the process zone 945 that may capacitively coupleto energize the process gas. The cathode 975 may be powered by anelectrode power supply 985 operated using, for example, an RF voltage ata power level of from about 10 Watts to about 1000 Watts. The capacitiveelectric field is substantially perpendicular to the plane of thesubstrate 930, and may accelerate the plasma species toward thesubstrate 930 to provide more vertically oriented anisotropic etching ofthe substrate. The frequency of the RF voltage applied to the processelectrodes 975, 980, and/or the inductor coil 965 is typically fromabout 50 KHz to about 60 MHz, and more typically about 2.2 or 13.56 MHz.In one version, the cathode 975 is also an electrode in a dielectric inthe electrostatic chuck 950.

The ceiling 990 of the process chamber 910 can be flat or rectangularshaped, arcuate, conical, dome-shaped, or multi-radius dome-shaped. Inone version, the inductor coil 965 covers at least a portion of theceiling 990 of the process chamber 910 in the form of a multi-radiusdome-shaped inductor coil having a “flattened” dome shape that providesmore efficient use of plasma source power and increased plasma ion fluxuniformity directly over the substrate 930 center.

When capacitively generated, the plasma formed in the process zone 945may also be enhanced using magnetically enhanced reactors (not shown),in which a magnetic field generator, such as a permanent magnet orelectromagnetic coils, are used to apply a magnetic field in the processzone 945 to increase the density and uniformity of the plasma. Themagnetic field may comprise a rotating magnetic field with the axis ofthe field rotating parallel to the plane of the substrate 930, asdescribed in U.S. Pat. No. 4,842,683, which is incorporated herein byreference in its entirety.

Spent process gas and etchant residue are exhausted from the processchamber 910 through an exhaust system 995 capable of achieving a lowpressure in the process chamber 910. A throttle valve 200 is provided inthe exhaust for controlling the pressure in chamber 910. Also, anoptical endpoint measurement system (not shown) may be used to determinecompletion of the etching process for a specific layer by measuring, forexample, the change in light emission of a particular wavelengthcorresponding to a detectable gaseous species or by otherinterferometric techniques.

To perform an etching process in the process chamber 910, an energizedprocess gas comprising etchant gas may be provided in the process zone945. By “energized process gas” it is meant that the process gas isactivated or energized to form one or more dissociated species,non-dissociated species, ionic species, and neutral species. The etchantgas composition may be selected to provide high etch rates, and highlyselective etching of a particular layer or layers that are being etched.

Method of Use of Etch/Strip Tool 600

An example of the use of etch/strip tool 600 is for the patterning of aconductive film or stack of conductive films into features used in anintegrated circuit. An example of such a process is illustrated in FIGS.10A-10E. According to this embodiment of the present invention, a waferor substrate, such as wafer 1000 as shown in FIG. 10A, is provided toapparatus 600 in a FOUP 620. Wafer 1000 includes a blanket depositedconductive film 1002 formed across the surface of the wafer. The film1002 can be for example, but not limited to, a polysilicon film or acomposite polysilicon/silicide film stack used to form gate electrodesor capacitor electrodes. In embodiments the conductive thin film 1002can include a dielectric hard mask, such as silicon nitride or siliconoxynitride film. The film can be a metal or metal alloy film, such asaluminum, copper or tungsten or a stack of metal films which include amain conductor 1001 and a barrier layer 1003 and an antireflectivecoating (ARC) 1005, such as titanium nitride (TiN)/aluminum(Al)/titanium nitride (TiN) film stack used for the formation ofinterconnects in an integrated circuit. Formed on conductive film 1002is a mask 1004, such as a well-known photoresist mask, which has apatterned defined therein which is to be formed in conductive film 1002.In order to process wafer 1000 in accordance with the present invention,the door to transfer chamber 610 is opened as is the connected door onFOUP 622 and wafer 1000 removed from FOUP 622 and brought intoatmospheric transfer chamber 610 by robot 612. Robot 612 then transfersthe wafer into CD module 700. In CD module 700 the critical dimensions(CD) of the photoresist layer 1004 is measured at various locationacross wafer 1000 as described with respect to CD measurement tool 700described in FIG. 7. If the CD measurements taken of CD measurement tool700 are out of compliance, then wafer 1000 can be removed from CD module700 by robot 612 and removed from apparatus 600. Alternatively, if theCD measurements are out of compliance, then wafer 1000 can be preparedfor rework by removing wafer 1000 from CD module 700 and inserting itinto strip chamber 400 whereby the photoresist mask 904 is stripped asdesired above. The stripped wafer is then removed from strip module 400and inserted it into wet clean chamber 200 where wafer 1000 is wetcleaned as described. Wafer 1000 can then be removed from clean module200 and removed from system 600 where it is now ready for application ofa new photoresist mask and patterning.

If the CD measurements of wafer 1000 are found to be in compliance withdesired results, then wafer 1000 is removed from CD module 700 andbrought into transfer chamber 610 by robot 612. The pressure within loadlock 606 is then brought to atmospheric pressure and the door 605between transfer chamber 610 and load lock 606 opened and wafer placedinto load lock 606 by robot 612. The door between transfer chamber 610and load lock 606 is then closed and the pressure within load lock 606reduced to the pressure within sub-atmospheric transfer chamber 630.

Next, the door 607 between single wafer load lock 606 andsub-atmospheric transfer chamber 630 is opened and robot 632 removeswafer 1000 from load lock 606 and brings it into transfer chamber 632.Next, if desired, a photoresist trim, as shown in FIG. 10B can beapplied to photoresist mask 904 to create a smaller dimensionphotoresist mask 1006 then is possible by photolithography alone. Thephotoresist trim can occur in either the etch chambers 900 or 900B orthe strip chamber 400B or 400C by exposing the photoresist mask 1004 tothin oxygen plasma. The photoresist trim step is optional.

Next, the door to etch chamber 900 is opened and wafer 1000 transferredfrom sub-atmospheric transfer chamber 630 into etch chamber 900 and thedoor closed. Next, conductive film 1002 is anisotropically etched inalignment with photoresist mask 1006 (or 1004) to pattern blanketdeposited conductive film 1002 into features 1008. The results of the CDmeasurements taken in CD module 700 can be used to determine the etchparameters, such as etch gas, time, pressure and power for the etchstep.

When etching a metal-containing material, the etchant gases may compriseone or more of halogen-containing gases, such as one or more of Cl₂,BCl₃, CCl₄, SiCl₄, CF₄, NF₃, SF₆, HBr, BBr₃, CHF₃, C₂F₂, and the like,and optionally, one or more additive gases, such as inert ornon-reactive gases, such as H₂, N₂, O₂, He—O₂ and the like. In anexemplary process, the anti-reflective material 1005 is etched byexposing the substrate 1000 to an energized process gas comprisingetchant gas comprising, for example, about 90 sccm Cl₂ and about 30 sccmBCl₃ at a pressure of about 8 mTorr, a source power level of about 1600Watts, a bias power level of about 145 Watts, a backside helium pressureof about 4 Torr and a cathode temperature of about 50° C. The main metalconductor 1001 may then be etched by an energized process gas comprisingetchant gas comprising, for example, about 80 sccm Cl₂, about 5 sccmBCl₃, and about 10 sccm CHF₃ at a pressure of about 14 mTorr, a sourcepower level of about 1600 Watts, a bias power level of about 150 Watts,a backside helium pressure of about 8 Torr and a cathode temperature ofabout 50° C. Thereafter, the diffusion barrier layer 1003, andoptionally a portion of the underlying oxide layer 1007, may be etchedby introducing an energized process gas comprising etchant gascomprising, for example, about 30 sccm Cl₂, about 5 sccm BCl₂, and about30 sccm N₂, or Ar at a pressure of about 10 mTorr, a source power levelof about 1600 Watts, a bias power level of about 125 Watts, a backsidehelium pressure of about 8 Torr and a cathode temperature of about 50°C.

After conductive film 1002 has been etched, the pressure in chamber 900brought up to the pressure in sub-atmospheric transfer chamber 630 andthe door 637 between etch module 900 and sub-atmospheric transferchamber 630 is opened and wafer 1000 removed from etch module 900 andbrought into sub-atmospheric transfer chamber 630 by robot 632. Next,wafer 1000 is transferred into strip module 400B and the door 633between strip module 400B and transfer chamber 630 sealed. Photoresistmask 1006 is then stripped, as shown in FIG. 10D, in strip module 400Bas described above. If the conductive film is a silicon film, wafer 1000can first be placed into wet clean module 200 (before strip module 400)and exposed to a quick diluted HF etch (100:1) to remove sputter siliconfrom the sidewalls of the photoresist 1006 to enable better stripping ofphotoresist 1006 in strip module 400.

The dry cleaning process may also comprise post-etch passivation of thesubstrate 500, particularly when conductive material has been etched inthe etching process, to remove or inactivate corrosive residue specieson the substrate 500. To passivate the substrate 500, energized processgas comprising passivating gas may be provided in the process zone 415.The passivating gas composition is selected to remove or inactivatecorrosive etchant residue, such as residue species 75 or to prevent theformation of corrosive or contaminant materials on the etched substrate.Passivating gas may comprise one or more of H₂O, NH₃, H₂O₂, O₂, N₂, CF₄,C₂F₆, CHF₃, H₂, C₃H₂F₆, C₂H₄F₂, or CH₃F. In one version, any gas orvapor containing hydrogen can serve as the passivating gas, includinghydrogen, water vapor, ammonia, methanol, hydrogen sulfide, and mixturesthereof. In another version, the passivation gases include (i) ammoniaand oxygen, or (ii) water vapor, with optional oxygen and nitrogen. Whenthe passivation gas comprises ammonia and oxygen, the volumetric flowratio of ammonia to oxygen is generally from about 1:1 to about 1:50,more typically from about 1:5 to about 1:20, and most typically about1:10. For a 5-liter capacity chamber 108, a gas flow comprises 300 sccmNH₃ and 3000 sccm O₂. Alternatively, a passivating gas comprising atleast about 80 volume % H₂, and typically about 100 volume % H₂, can beused to passivate the etchant residue 75. In one version, a passivatinggas comprises about 500 sccm H₂O energized at a power level of about1400 watts and introduced into the cleaning chamber 400 at a pressure ofabout 2 Torr for about 15 seconds. When a bubbler is used, an inertcarrier gas such as argon or helium can be passed through the bubbler totransport water vapor to the vacuum chamber. Optionally, oxygen,nitrogen or other additive can be added to the passivating gas toenhance passivating. In this version, the passivating gas comprises atleast about 20 volume % H₂O. The effect of the oxygen and nitrogenaddition depends on the ratio of the volumetric flow rate of water vapor(VH₂O) to the combined volumetric flow rates of oxygen and nitrogen(VO₂+VN₂). A suitable volumetric ratio of water vapor flow rate VH₂O tocombined volumetric flow rates of oxygen and nitrogen (VO₂+VN₂) for useas a passivating gas is at least about 1:2, more typically from about1:2 to about 2:1, and most typically about 1:1. As with the strippingprocess and as discussed in U.S. Pat. No. 5,545,289, the passivating maybe either a single step or multiple steps. In one version, the substrateis exposed to the passivating gas for a period of time of from about 10seconds to about 100 seconds, and more typically for about 45 seconds.In one version, a multi-cycle passivation process, for example a threecycle process, has been discovered to be particularly effective inpreventing corrosion.

Once photoresist layer 1006 has been sufficiently removed from substrate1000 and metal feature 1008 passivated (if desired), the door 633between strip module 400B and sub-atmospheric chamber 630 is opened andwafer 1000 is removed by robot 632. The pressure within load lock 608 isthen reduced or maintained at a sub-atmospheric pressure similar to thesub-atmospheric pressure in transfer chamber 630 and door 611 opened.Wafer 1000 is then transferred into load lock 608 and door 611 sealed.The pressure within load lock 608 is then brought up to atmosphericpressure by inserting a gas, such as nitrogen into load lock 608. Thedoor 609 is then opened and robot 612 removes wafer 1000 from load lock608. At this point, the wafer can be transferred into CD module 700 tocheck the critical dimensions of the patterned features 1080 or can betransferred into wet clean module 200 to remove any residualcontaminants or particles as shown in FIG. 10E. Wafer 1000 is thensubjected to a wet clean process in wet clean module 200. The wet cleancan vary from a light clean to an aggressive clean depending uponrequirements. After sufficient wet cleaning in module 200 transfer robot612 removes wafer 1000 from clean module 200 and can either (i) insertit into CD module 700 to check the critical dimension or (ii) can insertit into integrated particle monitor module 300 to determine thecleanliness of wafer 900. If wafer 900 is sufficiently clean then robot612 removes wafer 900 from integrated particle monitor 300 and transfersit into FOUP 622. If however, wafer 1000 is not sufficiently cleaned ofresidue, then wafer 1000 can be transferred into strip module 400coupled to atmospheric transfer chamber 610 and then into wet cleanmodule 200 or alternatively only into wet clean module 200. Wafer 1000can then once again be inspected in integrated particle monitor 618 andif sufficiently cleaned then removed by robot 612 into FOUP 622.

An example of another use of Etch/Strip tool 600 is in a damascene ordual damascene process such as illustrated in FIGS. 11A-11F. A damasceneor dual damascene process is used to form conductive features, such asgate electrodes, capacitor electrodes, interconnects, as well as vias,contacts and plugs in a dielectric layer. In a damascene process, awafer 1100 is provided which contains a blanket deposited dielectricfilm 1104, such as but not limited to silicon dioxide, siliconoxynitride, SiOF, BPSG, undoped silicon glass or organic dielectric, andorganic dielectrics and can be formed by any well-known technique, suchas but not limited to chemical vapor deposition (CVD), high densityplasma (HDP) CVD and sputtering. Dielectric layer 1100 can be a singledielectric film or can be a combination or stack of dielectric films. Amask 1102, such as a photoresist mask, is formed on dielectric film1104. Mask 1102 is patterned with openings 1103 formed which correspondto location where metal or conductive features are desired in dielectricfilm 1004.

According to this embodiment of the present invention, a wafer, such aswafer 1000, is provided to system 600 in a FOUP 620. To begin processingthe access door 621 between transfer chamber 612 and FOUP 622 is openedas it is corresponding door on FOUP 622. Robot 612 removes wafer 1100from FOUP 560 and brings it into transfer chamber 610. Robot 612 thentransfers wafer 1100 to CD measurement module 700. The criticaldimensions of photoresist mask 1102 is measured at various parts of thewafer to determine whether or not the critical dimensions of the maskare within spec. If the critical dimensions are outside of thespecifications desired wafer 1100 is removed from CD measurement tool700 by robot 612 and can be either removed from tool 600 or can beplaced in strip chamber 400 and then wet clean chamber 200 to removephotoresist mask 1102 so that wafer 1100 is ready for rework. If thecritical dimensions of photoresist mask 1102 are with specifications,then robot 612 removes wafer 1100 from CD module 700 and brings it intoatmospheric transfer chamber 612. The pressure (if not already atatmospheric pressure) within load lock 606 is then brought up toatmospheric pressure and the door 605 between load lock 606 andatmospheric transfer chamber 610 opened and wafer 1100 transferred intoload lock 606 and the door 605 sealed. The pressure within load lock 606is then evacuated to a pressure substantially equal to the pressurewithin sub-atmospheric transfer chamber 630. The door 607 between loadlock 606 and sub-atmospheric transfer chamber 630 is then opened androbot 632 removes wafer 1100 from load lock 606 and brings it intosub-atmospheric transfer chamber 630. Robot 632 then transfers wafer1100 into etch module 636 and the door 637 between etch module 636 andsub-atmospheric transfer chamber 630 sealed.

Next, as shown in FIG. 11B, the dielectric layer 1104 is etched, e.g.,anisotropically etched, in alignment with mask 1102 to form a patterneddielectric layer 1106 having openings 1108 which correspond to locationswhere conductive features are desired. Any well-known etch chemistry canbe used to etch dielectric film 1104. If dielectric film 1104 is asilicon dioxide film that can be etched with an etch chemistry, such asbut not limited to CF₄ or C₂F₆. Once dielectric layer 1104 has beensufficiently etched, the door 637 between etch chamber 900 andsub-atmospheric chamber 630 is opened and wafer 1100 removed by robot632. Robot 632 then transfers wafer 1100 into strip or dry clean module400B and the door between strip module 400B and sub-atomospherictransfer chamber 630 sealed. The photoresist mask is then stripped instrip module 400B as shown in FIG. 11C as described above. Once thephotoresist mask 1102 has been sufficiently removed, the door betweenstrip module 400 and transfer chamber 610 opened and robot 612 removeswafer 1100 from strip module 400 and brings it into atmospheric transferchamber 610. After the photoresist strip in module 400, the photoresistresidue and/or etch residue 1110 may remain on wafer 1100.

Robot 632 then transfers wafer 1100 into load lock 608 and door 611between load lock 608 and sub-atmospheric transfer chamber 630 sealed.The pressure within load lock 608 is then raised to atmospheric pressureby inserting a gas, such as nitrogen (N₂) therein. Once the chamberreaches atmospheric pressure, the door 609 between load lock 608 andatmospheric transfer chamber 610 is opened and robot 612 removes wafer1100 from load lock 608 and brings it into atmospheric transfer chamber610.

At this time, if desired, wafer 1100 can be inserted into criticaldimension monitoring tool 700 were the critical dimensions of thepatterned dielectric layer 1106 measured. To determine whether or notthe etch results are with specification, the CD results can be used tooptimize the etch parameters used in etch module 900 for subsequentlyetched wafers.

Next, the wafer 1100, as shown in FIG. 11C, is transferred into wetclean 200 and the door between wet clean module 200 and atmospherictransfer chamber 610 sealed. Wafer 1100 is then subjected to a wet cleanin wet clean module 200 as described above to remove residue 1110 asshown in FIG. 11D. Once a wafer has been sufficiently wet cleaned asshown in FIG. 11D, wafer 1100 is removed from clean module 614 by robot612 and transferred into integrated particle monitoring tool 618, wafer1100 is then scanned in integrated particle monitoring tool 300 to checkthe amount of particles contained on wafer 1100 to determine if wafer1100 has been sufficiently cleaned. If wafer 1100 has not beensufficiently cleaned, robot 612 removes wafer 1100 from integratedprocess module 300 and transfers it into either strip chamber 400 or wetclean 200 or to strip module 400 then wet clean module 200 dependingupon the type and amount of residue detected in integrated particlemonitoring module 300. If wafer 1100 has been sufficiently cleaned,wafer 1100 can then be removed from the integrated process monitoringtool 300 and transferred into atmospheric transfer chamber 610, wafer1100 is then transferred by robot 612 out of atmospheric transferchamber 610 and placed into a FOUP 622.

At this point, wafer 1100 can be transferred to a metal depositionmodule chamber whereby a metal film 1112 or stack of films is blanketdeposited over wafer 1100 as shown in FIG. 11E. Conductive film 1112fills the openings 1108 formed in dielectric layer 1106 and forms on topof dielectric layer 1106. Next, wafer 1100 is transferred to aplanarization module, such as a chemical mechanical planarizationmachine whereby the conductive film 1012 is planarized back to removethe conductive film from the top of the dielectric film 1106 as shown inFIG. 11F. The end result of the damascene process is the formation ofconductive features 1114 in dielectric layer 1106 which are planar withdielectric layer 1106. At this time, damascene process in accordancewith the present invention is complete. In an alternative embodiment ofthe damascene or dual damascene process, system 600 can be alteredwhereby instead of a second etch chamber 900B, a metal chamber, such asa chemical vapor deposition chamber or a sputtering chamber is usedtherein. In this way, after wafer 1100 has been sufficiently wet cleanedas shown in FIG. 11D and has passed particle inspection in module 300,the wafer 1100 can be transferred through load lock 606 back intosub-atmospheric transfer chamber 630 and placed into the conductive filmdeposition chamber were the film 1112 is deposited as shown in FIG. 11E.After deposition of the film 1112 the wafer would be removed from thedeposition chamber brought into the sub-atmospheric transfer chamber 632transferred through load lock 608 into the atmospheric transfer chamber510 where the wafer would be removed into a FOUP 620. If desired, thewafer could be transferred to into the integrated particle monitoringtool 618 to check for defects or particles formed during the depositionprocess and then the wafer removed from atmospheric transfer chamber610. Alternatively, the wafer 1100 could be subject to a dry clean inmodule 400 and/or a wet clean in module 200 after film deposition, ifdesired.

Another use of etch strip tool 600 is for the stripping of a siliconnitride film formed over a substrate and for the subsequent cleaning ofthe wafer to remove nitride residues and particles. Generally, siliconnitride films are removed with hot phosphoric acid which has a slow etchrate and therefore requires a long process time. As such, siliconnitride films are generally removed in a batch type (35-50 wafers at atime) process. Etch/strip tool 600 can be used to strip silicon nitridefilms from a wafer in a single wafer format and can do so withoutattacking or etching existing oxide films and can strip silicon nitridefilms in a economic cost effective amount of time.

In order to use tool 1600 to remove a silicon nitride film, all that isrequired is at least one etch module 900 on sub-atmospheric transferchamber 630 and at least one wet clean module 200 on atmospherictransfer chamber 610. In an embodiment of the silicon nitride stripprocess of the present invention, tool 600 contains multiple etchmodules 9000 on sub-atmospheric transfer chamber 630 and multiple wetclean chambers 200 on atmospheric transfer chamber 610. In an embodimentof the present invention, the number of wet clean chambers 200 and etchmodules 900 are balanced with the desired process times for the nitridestripping and cleaning process so the use of each module is maximized.

An example of the method of stripping a silicon nitride film utilizingapparatus 600 in accordance with an embodiment of the present inventionis illustrated in FIG. 16A-16C. Shown in FIG. 16A, is a substrate orwafer 1600 having a silicon nitride film 1604. In a typical use, siliconnitride film 1604 forms an oxidation resistant mask for the formation ofshallow trench isolation regions 1608 formed in the monocrystallinesilicon substrate 1602. (Typically a thin pad oxide 1606 is formedbetween the silicon nitride mask 1604 and the monocrystalline siliconsubstrate 1602). The mask 1604 is used to define locations wheretrenches are etched in substrate 1602 for trench isolation regions 1608to be formed. Additionally, silicon nitride mask 1604 provide anoxidation resistant mask preventing the oxidation of underlying siliconduring the formation of a thin thermal oxide 1610 in the trenchisolation region 1608. Subsequently the trench is filled with adeposited silicon dioxide film 1612 and polished back to be planar withthe top surface of nitride mask 1604 as shown in FIG. 16A. Nitride masksare also used in similar manner during the formation of LOCOS (LocalOxidation of Silicon) isolation regions. In both cases, after theformation of the isolation regions, it is desirable to remove thenitride mask 1604 without etching or affecting the integrity of theoxide isolation regions 1608.

Accordingly, a substrate or wafer having a nitride film, such assubstrate 1600 having a nitride film 1604 is brought to apparatus 600 ina FOUP 622. In order to process the wafer 1600 in accordance with thepresent invention, the door to transfer chamber 610 is opened, as is theconnected door to FOUP 622 and wafer 1600 is removed from FOUP 622 andbrought into atmospheric transfer chamber 610 by robot 612. The door 605between atmospheric transfer chamber 610 and load lock 606 is thenopened and robot 612 transfers wafer 1600 into load lock 606. The door605 is sealed and load lock 606 pumped down to the pressure withinsub-atmospheric transfer chamber 630. Once the pressure withinsub-atmospheric transfer chamber 630 is reached, door 607 opens androbot 632 removes wafer 1600 from load lock 606 and brings it intosub-atmospheric transfer chamber 630. Wafer 1600 is then moved fromsub-atmospheric transfer chamber into an etch module 900 and the doorbetween the etch module and the sub-atmospheric transfer chamber sealedand the etch chamber pumped down to the desired process pressure.

Next, the silicon nitride film 1604 is stripped with a dry plasma usinga chemistry comprising, for example CF₄ or C₂F₆. The wafer is exposed tothe stripping plasma in module 900 until the silicon nitride mask 1604has been sufficiently removed. After removing silicon nitride film 1604,silicon residue 1614 may be left on silicon monocrystalline substrate1602 (or pad oxide 1606 if used) as shown in FIG. 16B.

After stripping silicon nitride mask 1604, the pressure within stripmodule 900 is brought to the pressure within sub-atmospheric transferchamber 630 and the door between strip module 900 and sub-atmospherictransfer chamber 630 opened. Robot 632 then removes substrate 1600 fromstrip module 900 and places it into one of the single wafer load locks1606 or 1608. The pressure within the load lock is then brought up toatmospheric pressure and the door between the atmospheric transferchamber and the load lock opened and robot 612 removes the substrate1600 from the load lock and places it into wet clean module 200. In wetmodule 200 wafer 1600 is exposed to a wet cleaning process as describedabove. The wet clean can vary from a light clean consisting of only DIwater rinse to a heavy clean utilizing cleaning solutions and etchantsas described above.

Once wafer 1600 has been sufficiently cleaned of particles and residue1614 the wafer is spun dried in module 200. Next, wafer 1600 is removedfrom clean module 200 by robot 612 and brought into atmospheric transferchamber 610. Robot 1612 can either i) bring the wafer into FOUP 622 or624 whereby processing is complete, or can ii) bring wafer 1600 intointegrated particle monitoring tool 300 where the surface is checked forparticles and residue. If substrate 1600 is placed into integratedparticle monitoring tool 300 after monitoring the surface forcontaminants depending upon the results of the scan, the wafer is eithermoved into FOUP 622 or is sent back to either wet clean chamber 200 orback into etch module 900 or both for further processing. Additionally,information gained from the surface monitoring can be used by controller124 to determine the process parameters for stripping the siliconnitride 1604 on subsequent wafers and can be used to determine cleaningparameters for cleaning subsequent wafer in wet cleaning module 200. Forexample, if significant silicon nitride is present during the scan inIPM module 300, the exposure time in etch module 900 can be increased orthe process chemistry altered for subsequent wafers, or if particles arefound a more aggressive cleaning process can be used on subsequentwafers. The change in process parameters would be determined by complexcontroller 124 from a stored look up table or formula which relates theprocess parameters to the particle scan of wafer 1600. It is to beappreciated that silicon nitride films used for other purposes than forthe formation of isolation regions can be stripped or removed in asimilar manner.

Integrated Clean/Gate Tool

FIG. 12 illustrates another atmospheric/sub-atmospheric process tool1200 in accordance with the present invention. Process tool 1200 is anintegrated clean/gate fabrication tool which can be used to clean awafer and then form a high quality gate dielectric and a gate electrodeon a silicon monocrystalline substrate or epitaxial layer. In anembodiment of the present invention, the process tool 1200 includes amodule for forming a high dielectric constant film, such as metal oxidedielectric, such as tantalum pentaoxide or titanium oxides.

Integrated clean/gate tool 1200 includes an atmospheric platform 1202and a sub-atmospheric platform 1204. The sub-atmospheric platform 1204and the atmospheric platform 1202 are coupled together by a single waferload lock 1206 and preferably by two single wafer load locks 1206 and1208. Atmospheric platform 1202 includes a central atmospheric transferchamber 1210 having a wafer handling device 1212 contained therein.Directly attached to atmospheric transfer chamber 1210 is a single waferwet cleaning module 200, an integrated particle monitoring tool 300 andan integrated thickness monitoring tool 1290. Wet cleaning module 200,integrated particle monitoring tool 300, and integrated thicknessmonitoring tool 1290 are each connected to transfer chamber 102 througha separately closable opening or slit valve. Transfer chamber 1210 ismaintained at substantially atmospheric pressure during operation. In anembodiment of the present invention, the atmospheric transfer chamber1210 can be opened or exposed to the atmosphere of a semiconductorfabrication “clean room” in which it is located. In such a case, thetransfer chamber 1210 may contain an overhead filter, such as ahepafilter to provide a high velocity flow of clean air or an inertambient such as N₂, to prevent contaminants from finding their way intothe atmospheric transfer chamber. In other embodiments, the atmospherictransfer chamber 1210 is a closed system and may contain its ownambient, of clean air or an inert ambient, such as nitrogen gas (N₂).

Atmospheric transfer chamber 1210 includes a wafer handling robot 1212which can transfer a wafer from one module to another module inatmospheric process tool 1202. In an embodiment of the presentinvention, the wafer handler 1212 is a dual blade, single arm, andsingle wrist robot. The handling blades both rotate about a single axiscoupled to the end of the single arm.

Also coupled to atmospheric transfer chamber 1210 is at least one waferinput/output module 1220 or pod for providing and taking wafers to andfrom system 1200. In an embodiment of the present invention, the waferinput/output module is a front opening unified pod (FOUP) which containsa cassette of between 13-25 horizontally spaced wafers. In an embodimentof the present invention, apparatus 1200 includes two FOUPs 1220 and1222, one for providing wafers into system 1200 and one for removingcompleted or processed wafers from system 1200. Atmospheric transferchamber 1210 contains sealable access doors 521 for allowing wafer to betransferred into and out of atmospheric transfer chamber 1210. There isan access door 1221 for each FOUP, and each access door is attached to acounterpart door on each FOUP so that when the transfer chamber accessdoor 1221 slides open, it opens the door to the FOUP to provide accessfor the robot 1212 into the FOUP.

Coupled to the opposite sides of atmospheric transfer chamber 1210 thenFOUP 1220 and 1222 is a single wafer load lock 1206 and typically asecond single wafer load lock 1208. Single wafer load locks 1206 and1208 enable a wafer to be transferred from the atmospheric conditions intransfer chamber 1210 to the sub-atmospheric conditions of platform 1204and allow wafer to be transferred from sub-atmospheric platform 1204 toatmospheric transfer chamber 1210. A sealable door 1205 is locatedbetween single wafer load lock 1206 and atmospheric transfer chamber1210. A sealable door 1207 is located between sub-atmospheric transferchamber 1224 and load lock 1206. Similarly, a sealable door is locatedbetween atmospheric transfer chamber 1210 and load lock 1208, and asealable door 111 is located between load lock 1208 and sub-atmospherictransfer chamber 1224. Coupled to each of the load locks 1206 and 1108is a vacuum source which enables the pressure inside load locks 1206 and1208 to be independently lowered. Additionally, coupled to each loadlock 1206 and 1208 is a gas inlet for providing, for example, an inertgas into the load lock to enable the pressure within the load lock to beraised to, for example, to atmospheric pressure. In this way, thepressure within the load lock 1206 and 1208 can be matched to either thepressure within atmospheric transfer chamber 1210 or the pressure withinsub-atmospheric transfer chamber 1224. Although, load locks 1206 and1208 are ideally low volume single wafer load locks to enable fast wafertransfers between the atmospheric transfer chamber and thesub-atmospheric transfer chamber, load locks 1206 and 1208, however, canbe larger multiple wafer load locks which can hold multiple wafers at asingle time, if desired.

Attached to the opposite ends of the single wafer load locks 1206 and1208 is a sub-atmospheric transfer chamber 1224 having a wafer handlingdevice 1226 contained therein. Sub-atmospheric transfer chamber 1224 issaid to be sub-atmospheric transfer chamber because transfer chamber1224 is held at a pressure less than atmospheric pressure and preferablybetween 10⁻³ to 50 Torr while in operation and while passing the wafersto the various sub-atmospheric process modules coupled thereto.

Directly attached to sub-atmospheric transfer chamber 1224 is a singlewafer thermal process chamber 1300 which can be used to grow a silicondioxide or silicon oxynitride or silicon nitride dielectric film onwafer. Additionally, also directly attached to sub-atmospheric transferchamber 1224 is a polysilicon deposition chamber 1400 which can be usedto form a polysilicon film, for example, a polysilicon gate electrode.In an embodiment of the present invention, process tool 1200 includes ahigh k dielectric film deposition module 1700 directly attached tosub-atmospheric transfer chamber 1224 to enable the formation of a highdielectric constant film, such as metal dielectrics, e.g. titaniumoxides, tantalum oxides, zirconium oxide, and hafnium oxides.Additionally, in an embodiment of the present invention, apparatus 1200includes a second thermal process chamber 1300 in order to betterbalance the wafer throughput of wafer through process tool 1100. Thermalprocess tool 1300 and polysilicon deposition tool 1400 are connected tosub-atmospheric transfer chamber 1224 through separately closable andsealable openings.

Apparatus 1100 also includes a system computer or control device 124which is coupled and controls each module coupled to atmospherictransfer chamber 1210 and controls each sub-atmospheric module coupledto sub-atmospheric transfer chamber 1224, controls load locks 1206 and1208 as well as the operation of robots 1212 and 1226. Computer 124enables a feedback from one module to be used to control the flow of awafer through system 1200 and/or to control the process or operation ofthe other modules of system 1200.

Thermal Process Module

An example of a thermal process module which can be used as thermalprocess modules 1300 or 1300B is illustrated in FIG. 13A-B. FIG. 13A-Billustrates an insitu steam generation (ISSG) process tool 1300 whichcan be used to grow an oxide film, such as a high quality gatedielectric film. ISSG chamber 1300 can be adapted to include nitrogencontaining gas so that silicon nitride films or silicon oxynitride filmscan also be formed.

Module 1300 as shown in FIG. 13A, includes an evacuated process chamber1313 enclosed by a sidewall 1314 and a bottom wall 1315. Sidewall 1314and bottom wall 1315 are preferably made of stainless steel. The upperportion of sidewall 1314 of chamber 1313 is sealed to window assembly1317 by “O” rings 1316. A radiant energy light pipe assembly 1318 ispositioned over and coupled to window assembly 1317. The radiant energyassembly 1318 includes a plurality of tungsten halogen lamps 1319, forexample Sylvania EYT lamps, each mounted into a light pipe 1321 whichcan be a stainless steel, brass, aluminum or other metal.

A substrate or wafer 1361 is supported on its edge in side chamber 1313by a support ring 1362 made up of silicon carbide. Support ring 1362 ismounted on a rotatable quartz cylinder 1363. By rotating quartz cylinder1363 support ring 1362 and wafer 1361 can be caused to rotate. Anadditional silicon carbide adapter ring can be used to allow wafers ofdifferent diameters to be processed (e.g., 150 mm as well as 200 mm).The outside edge of support ring 1362 preferably extends less than twoinches from the outside diameter of wafer 1361. The volume of chamber1313 is approximately two liters.

The bottom wall 1315 of apparatus 1300 includes a gold coated topsurface 1311 for reflecting energy onto the backside of wafer 1361.Additionally, rapid thermal heating apparatus 1300 includes a pluralityof fiber optic probes 1370 positioned through the bottom wall 1315 ofapparatus 1300 in order to detect the temperature of wafer 1361 at aplurality of locations across its bottom surface. Reflections betweenthe backside of the silicon wafer 1361 and reflecting surface 1311create a blackbody cavity which makes temperature measurementindependent of wafer backside emissivity and thereby provides accuratetemperature measurement capability.

Rapid thermal heating apparatus 1300 includes a gas inlet 1369 formedthrough sidewall 1314 for injecting process gas into chamber 1313 toallow various processing steps to be carried out in chamber 1313.Coupled to gas inlet 1369 is a source, such as a tank, of oxygencontaining gas such as O₂ and a source, such as a tank, of hydrogencontaining gas such as H₂. In an embodiment of the present invention, anitrogen containing gas, such as NH₃, or N₂O is produced to enable theformation of silicon oxynitride films. Positioned on the opposite sideof gas inlet 1369, in sidewall 1314, is a gas outlet 1368. Gas outlet1368 is coupled to a vacuum source, such as a pump, to exhaust processgas from chamber 1313 and to reduce the pressure in chamber 1313. Thevacuum source maintains a desired pressure while process gas iscontinually fed into the chamber during processing.

Lamps 1319 include a filament wound as a coil with its axis parallel tothat of the lamp envelope. Most of the light is emitted perpendicular tothe axis towards the wall of the surrounding light pipe. The light pipelength is selected to at least be as long as the associated lamp. It maybe longer provided that the power reaching the wafer is notsubstantially attenuated by increased reflection. Light assembly 1318preferably includes 187 lamps positioned in a hexagonal array or in a“honeycomb shape” as illustrated in FIG. 13B. Lamps 1319 are positionedto adequately cover the entire surface area of wafer 1361 and supportring 1362. Lamps 1319 are grouped in zones which can be independentlycontrolled to provide for extremely uniform heating of wafer 1361. Heatpipes 1321 can be cooled by flowing a coolant, such as water, betweenthe various heat pipes. The radiant energy source 1318 comprising theplurality of light pipes 1321 and associated lamps 1319 allows the useof thin quartz windows to provide an optical port for heating asubstrate within the evacuative process chamber.

Window assembly 1317 includes a plurality of short light pipes 1341which are brazed to upper/lower flange plates which have their outeredges sealed to an outer wall 1344. A coolant, such as water, can beinjected into the space between light pipes 1341 to serve to cool lightpipes 1341 and flanges. Light pipes 1341 register with light pipes 1321of the illuminator. The water cooled flange with the light pipe patternwhich registers with the lamp housing is sandwiched between two quartzplates 1347 and 1348. These plates are sealed to the flange with “O”rings 1349 and 1351 near the periphery of the flange. The upper andlower flange plates include grooves which provide communication betweenthe light pipes. A vacuum can be produced in the plurality of lightpipes 1341 by pumping through a tube 1353 connected to one of the lightpipes 1341 which in turn is connected to the rest of the pipes by a verysmall recess or groove in the face of the flange. Thus, when thesandwiched structure is placed on a vacuum chamber 1313 the metalflange, which is typically stainless steel and which has excellentmechanical strength, provides adequate structural support. The lowerquartz window 1348, the one actually sealing the vacuum chamber 1313,experiences little or no pressure differential because of the vacuum oneach side and thus can be made very thin. The adapter plate concept ofwindow assembly 1317 allows quartz windows to be easily changed forcleaning or analysis. In addition, the vacuum between the quartz windows1347 and 1348 of the window assembly provides an extra level ofprotection against toxic gasses escaping from the reaction chamber.

Rapid thermal heating apparatus 1300 is a single wafer reaction chambercapable of ramping the temperature of a wafer 1361 or substrate at arate of 25-100° C./sec. Rapid thermal heating apparatus 1300 is said tobe a “cold wall” reaction chamber because the temperature of the waferduring the oxidation process is at least 400° C. greater than thetemperature of chamber sidewalls 1314. Heating/cooling fluid can becirculated through sidewalls 1314 and/or bottom wall 1315 to maintainwalls at a desired temperature. For a steam oxidation process utilizingthe insitu moisture generation of the present invention, chamber walls1314 and 1315 are maintained at a temperature greater than roomtemperature (23° C.) in order to prevent condensation. Rapid thermalheating apparatus 1300 is preferably configured as part of a “clustertool” which includes a load lock and a transfer chamber with a roboticarm.

Chemical Vapor Deposition Module

FIGS. 14A-14C illustrates a low pressure chemical vapor deposition(LPCVD) chamber 1400 which can be used as silicon deposition module 1400to deposit a doped or undoped polycrystalline silicon film. The LPCVDchamber 1400 illustrated in FIGS. 14A-14C is constructed of materialssuch that, in this embodiment, a pressure of greater than or equal to100 Torr can be maintained. For the purpose of illustration, a chamberof approximately in the range of 5-6 liters is described. FIG. 14Aillustrates the inside of process chamber body 1445 in a “wafer-process”position. FIG. 14B shows the same view of the chamber in a“wafer-separate” position. FIG. 14C shows the same cross-sectional sideview of the chamber in a “wafer-load” position. In each case, a wafer500 is indicated in dashed lines to indicate its location in thechamber.

FIG. 14A-14C show chamber body 1445 that defines reaction chamber 1490in which the thermal decomposition of a process gas or gases takes placeto form a film on a wafer (e.g., a CVD reaction). Chamber body 1445 isconstructed, in one embodiment, of aluminum and has passages 1455 forwater to be pumped therethrough to cool chamber 1445 (e.g., a“cold-wall” reaction chamber). Resident in chamber 1490 is resistiveheater 1480 including, in this view, susceptor 1405 supported by shaft1465. Susceptor 1405 has a surface area sufficient to support asubstrate such as a semiconductor wafer 1400 (shown in dashed lines).

Process gas enters otherwise sealed chamber 1490 through gasdistribution port 1420 in a top surface of chamber lid 1430 of chamberbody 1445. The process gas then goes through blocker plate 1424 todistribute the gas about an area consistent with the surface area of awafer. Thereafter, the process gas is distributed through perforatedface plate 1425 located, in this view, above resistive heater 1480 andcoupled to chamber lid 1430 inside chamber 1490. One objective of thecombination of blocker plate 1424 with face plate 1425 in thisembodiment is to create a uniform distribution of process gas at thesubstrate, e.g., wafer.

A substrate 1408, such as a wafer, is placed in chamber 1490 onsusceptor 1405 of heater 1480 through entry port 1440 in a side portionof chamber body 1445. To accommodate a wafer for processing, heater 1480is lowered so that the surface of susceptor 1405 is below entry port1440 as shown in FIG. 14C. By a robotic transfer mechanism 1226, a wafer1408 is loaded by way of, for example, a transfer blade 1441 intochamber 1490 onto the superior surface of susceptor. Once loaded, entry1440 is sealed and heater 1480 is advanced in a superior (e.g., upward)direction toward face plate 1425 by lifter assembly 1460 that is, forexample, a stepper motor. The advancement stops when the wafer 500 is ashort distance (e.g., 400-700 mils) from face plate 1425 (see FIG. 14A).In the wafer-process position, chamber 1490 is effectively divided intotwo zones, a first zone above the superior surface of susceptor 1405 anda second zone below the inferior surface of susceptor 1405. It isgenerally desirable to confine polysilicon film formation to the firstzone.

At this point, process gas controlled by a gas panel flows into chamber1490 through gas distribution port 1420, through blocker plate 1424 andperforated face plate 1425. Process gas thermally decomposes to form afilm on the wafer. At the same time, an inert bottom-purge gas, e.g.,nitrogen, is introduced into the second chamber zone to inhibit filmformation in that zone. In a pressure controlled system, the pressure inchamber 1490 is established and maintained by a pressure regulator orregulators coupled to chamber 1490. In one embodiment, for example, thepressure is established and maintained by baretone pressure regulator(s)coupled to chamber body 1445 as known in the art. In this embodiment,the baretone pressure regulator(s) maintains pressure at a level ofequal to or greater than 150 Torr.

Residual process gas is pumped from chamber 1490 through pumping plate1485 to a collection vessel at a side of chamber body 1445 (vacuumpumpout 1431). Pumping plate 1485 creates two flow regions resulting ina gas flow pattern that creates a uniform silicon layer on a substrate.

Pump 1432 disposed exterior to apparatus provides vacuum pressure withinpumping channel 1440 (below channel 1440 in FIGS. 14A-14C) to draw boththe process and purge gases out of the chamber 1490 through vacuumpump-out 1431. The gas is discharged from chamber 1490 along a dischargeconduit 1433. The flow rate of the discharge gas through channel 1440 ispreferably controlled by a throttle valve 1434 disposed along conduit1433. The pressure within processing chamber 1490 is monitored withsensors (not shown) and controlled by varying the cross-sectional areaof conduit 1433 with throttle valve 1434. Preferably, a controller 124receives signals from the sensors that indicate the chamber pressure andadjusts throttle valve 1434 accordingly to maintain the desired pressurewithin chamber 1490. A suitable throttle valve for use with the presentinvention is described in U.S. Pat. No. 5,000,225 issued to Murdoch andassigned to Applied Materials, Inc., the complete disclosure by which isincorporated herein by reference.

Once wafer processing is complete, chamber 1390 may be purged, forexample, with an inert gas, such as nitrogen. After processing andpurging, heater 1480 is advanced in an inferior direction (e.g.,lowered) by lifter assembly 1460 to the position shown in FIG. 14B. Asheater 1480 is moved, lift pins 1495, having an end extending throughopenings or throughbores in a surface of susceptor 1405 and a second endextending in a cantilevered fashion from an inferior (e.g., lower)surface of susceptor 1405, contact lift plate 1475 positioned at thebase of chamber 1490. As is illustrated in FIG. 14B, in one embodiment,at the point, lift plate 1475 remains at a wafer-process position (i.e.,the same position the plate was in FIG. 14A). As heater 1480 continuesto move in an inferior direction through the action of assembly 1460,lift pins 1495 remain stationary and ultimately extend above thesusceptor or top surface of susceptor 1405 to separate a processed waferfrom the surface of susceptor 1405. The surface of susceptor 1405 ismoved to a position below opening 1440.

Once a processed wafer is separated from the surface of susceptor 1405,transfer blade 1441 of a robotic mechanism is inserted through opening1440 beneath the heads of lift pins 1495 and a wafer supported by thelift pins. Next, lifter assembly 1460 inferiorly moves (e.g., lowers)heater 1480 and lifts plate 1475 to a “wafer load” position. By movinglift plates 1475 in an inferior direction, lift pins 1495 are also movedin an inferior direction, until the surface of the processed wafercontacts the transfer blade. The processed wafer is then removed throughentry port 1440 by, for example, a robotic transfer mechanism 1226 thatremoves the wafer and transfers the wafer to the next processing step. Asecond wafer may then be loaded into chamber 1490. The steps describedabove are generally reversed to bring the wafer into a process position.A detailed description of one suitable lifter assembly 1460 is describedin U.S. Pat. No. 5,772,773, assigned to Applied Materials, Inc. of SantaClara, Calif.

In a high temperature operation, such as LPCVD processing to form apolycrystalline silicon film, the heater temperature inside chamber 1490can be as high as 750° C. or more. Accordingly, the exposed componentsin chamber 1490 must be compatible with such high temperatureprocessing. Such materials should also be compatible with the processgases and other chemicals, such as cleaning chemicals (e.g., NF₃) thatmay be introduced into chamber 1490. Exposed surfaces of heater 1480 maybe comprised of a variety of materials provided that the materials arecompatible with the process. For example, susceptor 1405 and shaft 1465of heater 1480 may be comprised of similar aluminum nitride material.Alternatively, the surface of susceptor 1405 may be comprised of highthermally conductive aluminum nitride materials (on the order of 95%purity with a thermal conductivity from 140 W/mK while shaft 1465 iscomprised of a lower thermally conductive aluminum nitride. Susceptor1405 of heater 1480 is typically bonded to shaft 65 through diffusionbonding or brazing as such coupling will similarly withstand theenvironment of chamber 1490.

FIG. 14A also shows a cross-section of a portion of heater 1480,including a cross-section of the body of susceptor 1405 and across-section of shaft 1465. In this illustration, FIG. 14A shows thebody of susceptor 1405 having two heating elements formed therein, firstheating element 1450 and second heating element 1457. Each heatingelement (e.g., heating element 1450 and heating element 1457) is made ofa material with thermal expansion properties similar to the material ofthe susceptor. A suitable material includes molybdenum (Mo). Eachheating element includes a thin layer of molybdenum material in a coiledconfiguration.

In FIG. 14A, second heating element 1457 is formed in a plane of thebody of susceptor 1405 that is located inferior (relative to the surfaceof susceptor in the figure) to first heating element 1450. First heatingelement 1450 and second heating element 1457 are separately coupled topower terminals. The power terminals extend in an inferior direction asconductive leads through a longitudinally extending opening throughshaft 1465 to a power source that supplies the requisite energy to heatthe surface of susceptor 1405. Extending through openings in chamber lidare two pyrometers, first pyrometer 1410 and second pyrometer 1415. Eachpyrometer provides data about the temperature at the surface ofsusceptor 1405 (or at the surface of a wafer on susceptor 1405). Also ofnote in the cross-section of heater 1480 as shown in FIG. 14A is thepresence of thermocouple 1470. Thermocouple 1470 extends through thelongitudinally extending opening through shaft 1465 to a point justbelow the superior or top surface of susceptor 1405.

High K Dielectric Deposition Module

A high k dielectric deposition module 1700 which can be used in thepresent invention is shown in FIG. 17A and includes a liquid deliverysystem, chemical vapor deposition (CVD) chamber, exhaust system andremote plasma generator which together comprises a unique systemespecially useful in depositing thin metal-oxide films as well as otherfilms requiring vaporization of low volatility precursor liquids. Thesystem also provides for an in-situ cleaning process for the removal ofmetal-oxide films deposited on interior surfaces of a depositionchamber. The system also has application in the use of fabricatingmetal-oxide dielectrics useful in making ultra large scale integration(ULSI) DRAM and other advanced feature electronic devices which requirethe deposition of high dielectric constant materials. In general,devices that can be made with the system of the present invention arethose devices characterized by having one or more layers of insulating,dielectric or electrode material on a suitable substrate such assilicon. One skilled in the art will appreciate the ability to usealternative configuration and process details to the disclosed specificswithout departing from the scope of the present invention. In otherinstances, well known semiconductor processing equipment and methodologyhave not been described in order not to unnecessarily obscure thepresent invention.

FIG. 17A is a perspective view of the high k deposition module 1700showing the relative positions of the main components of the presentinvention. High k deposition module 1700 contains a processing chamber1702, a heat exhaust system 1704, a remote plasma generator 1706 and avapor delivery system 1708. Also shown in FIG. 17A is a sub-atmospherictransfer chamber 1224. Processing chamber 1702 is comprised of lid 1710and chamber body 1712 and is attached to central transfer chamber 1224.Gases supplied via liquid delivery system 1708 are provided into aprocessing region (not shown) within chamber 1708 via temperaturecontrolled conduits formed within inlet block 1714, mixing block 1716and central block 1718. Cartridge style heaters 1720 are integrallyformed into each block and, in conjunction with individual thermocouplesand controllers, maintain temperature set points within the conduits.For clarity, individual thermocouples and controllers have been omitted.Not visible in FIG. 17A but an aspect of the module is embedded lidheater located intregal to lid 1710 beneath heater backing plate 1722.

Chamber 1702 processing by-products are exhausted via heated exhaustsystem 1704 which is coupled to chamber 1702 via exhaust port 1724. Alsoshown are isolation valve 1726, throttle valve 1728, chamber by-pass1730, cold trap 1732 and cold trap isolation valve 1734. For clarity,specific embodiments of vacuum pump and wafer fabrication plant exhausttreatment systems are not shown. In order to provide a clearerrepresentation of the interrelationship between and relative placementof each of the components of heated exhaust system 1704, the jacket typeheaters, thermocouples and controllers used to maintain setpointtemperatures in exhaust port 1724, isolation valve 1726, throttle valve1728, chamber by-pass 1730, and by-pass line 1736 have been omitted.

Activated species are generated by remote plasma generator 1706 andprovided to a processing region within chamber 1702 via conduits withinactivated species inlet block 1740, activated species block 1742 andcentral block 1718. Other components of remote plasma generator 1706such as magnetron, auto tuner controller 1746, and auto tuner 1748 arevisible in FIG. 17A.

One of the main components of liquid delivery system 1708 is liquid flowmeter 1750 and vaporizer 1752. Three-way inlet valve 1754 allows eitherprecursor 1756 or solvent 1758 into vapor delivery system 1708. Heatexchangers 1760 and 1762 preheat carrier gases and process gasesrespectively. Heated carrier gases travel via a carrier gas supply line1764 to vaporizer 1752 in order to facilitate more complete vaporizationwithin vaporizer 1752 as well as carry vaporized liquids to chamber1702. After vaporization in vaporizer 1752, chamber by-pass valve 1766allows vapor to be ported either to processing region in chamber 1702via outlet 1762 or to exhaust system 1704 via outlet 1768 which iscoupled to heated by-pass line 1736. A jacket style heater, thermocoupleand controller which maintain the temperature of chamber by-pass valve1766 and vaporizer precursor line 1770 as well as the jacket styleheater, thermocouple and controller which maintain the temperature ofby-pass line 1736 have been omitted so as not to obscure the componentsof liquid delivery system 1708 and their relationship to chamber 1702and heated exhaust system 1704.

The size and dimensions of the various components and the placement ofthese components in relation to each other are determined by the size ofthe substrate on which the processes of the present invention are beingformed. A preferred embodiment of the invention will be described hereinwith reference to a high k deposition module 1700 adapted to processcircular substrate, such as a silicon wafer, having a 200 mm diameter.Although described in reference to a single substrate, one of ordinaryskill in the art of semiconductor processing will appreciate that themethods and various embodiments of the present invention are adaptableto the processing of multiple substrates within a single chamber 1702.

FIG. 17B is a cross sectional view of chamber assembly 1702 ofprocessing system 1700 of FIG. 17A. Chamber body 1712 and heated chamberlid 1710, which is hingedly connected to chamber body 1712, togetherwith O-ring 1770 form a temperature and pressure controlled environmentor processing region 1772 which enables deposition processes and otheroperations to be performed within processing region 1772. Chamber body1712 and lid 1710 are preferably made of a rigid material such asaluminum, various nickel alloys or other materials having good thermalconductivity. O-ring 1770 could be formed from Chemraz, Kalrez, Viton orother suitable sealing material.

When lid 1710 is closed as shown in FIG. 17B, an annular processingregion 1772 is formed which is bounded by showerhead 1774, substratesupport 1776 and the walls of chamber body 1712. Substrate support 1776(shown in the raised position for processing) extends through the bottomof chamber body 1712. Embedded within substrate support 1776 is aresistive heater which receives power via resistive heating elementelectrical connector 1778. A thermocouple in thermal contact withsubstrate support 1776 senses the temperature of substrate support 1776and is part of a closed loop control circuit which allows precisetemperature control of heated substrate support 1776. Substrate support1776 and substrate 1701 are parallel to showerhead 1774. Substrate 1701is supported by the upper surface of support 1776 and is heated by theresistive heaters within substrate support 1776 to processingtemperatures of, for example, between about 400° C. and 500° C. forTantalum films formed using the methods and apparatus of the presentinvention.

Processing chamber 1702 is coupled to sub-atmospheric transfer chamber1224 via opening 1780. A slit valve 1782 seals processing region 1772from sub-atmospheric transfer chamber 1224. Substrate support 1776 mayalso move vertically into alignment with opening 1780 which, when slitvalve 1782 is open, allows substrates to move between the processingregion 1772 and sub-atmospheric transfer chamber 1224. Substrate 1701can be a substrate used in the manufacture of semiconductor productssuch as silicon substrates and gallium arsenide substrates and can beother substrates used for other purposes such as substrates used in theproduction of flat panel displays.

Pumping passage 1784 and outlet port 1786 formed within chamber body1712 for removing by products of processing operations conducted withinprocessing region 1772. Outlet port 1786 provides fluid communicationbetween components of heated exhaust system 1704 and processing region1772.

Turning now to gas delivery features of chamber 1702, both processgas/precursor mixture from liquid delivery system 1708, via conduit1788, and activated species from remote plasma generator system 1706,via conduit 1790, flow through central conduit 1792 to bore through 1794formed in lid 1710. From there, gases and activated species flow throughblocker plate 1796 and showerhead 1774 into processing region 1772. Afeature of showerhead 1774 of the present invention is the plurality ofapertures.

Process gas and vaporized precursors and mixtures thereof are providedto central bore through 1794 via temperature controlled conduits formedintegral to heated feed through assembly 1798. Heated feed throughassembly 1798 is comprised of central block 1799, mixed deposition gasfeed through block 1716 and inlet and mixing block 1714. Although theembodiment represented in chamber 1702 of FIG. 17B indicates a heatedfeed through assembly 1798 comprising three separate blocks 1718, 1716,and 1714, one of ordinary skill will appreciate that the blocks can becombined such as replacing inlet and mixing block 1714 and feed throughblock 1716 with a single block without departing from the spirit of thepresent invention. Additionally, a plurality of cartridge heaters 1720are disposed internal to each of the aforementioned blocks and proximateto the conduits 1792, 1788, 1797, 1795, and 1793 which maintain asetpoint in each conduit utilizing separate controllers andthermocouples for the heater of a particular conduit. For clarity, theseparate thermocouples and controllers have been omitted.

Lid 1710 is also provided with a cooling channel 1791 which circulatescooling water within that of lid 1710 in proximity to o-ring 1770.Cooling channel 1791 allows lid 1710 to maintain the temperaturespreferred for advantageous heating of showerhead 1774 while protectingo-ring 1770 from the high temperatures which degrade the sealingqualities of o-ring 1770 thereby making o-ring 1770 more susceptible toattack by the reactive species generated and supplied to processingregion 1772 by remote plasma generator 1706.

Another feature of processing chamber 1702 of the present invention alsoshown in FIG. 17B is embedded resistive heater 1789 within lid 1710.This feature of chamber assembly 1702 provides elevated temperatures inlid 1710 in proximity to central bore through 1794 and the area betweenthe lower surface of the lid 1710 and showerhead upper surface 1787. Theregion between lid 1710 and showerhead upper surface 1787 is referred toas the “gas box”. Formed within the top surface of lid 1710 is anannular groove shaped according to the size and shape of embedded heater1789 in order to increase surface contact and heat transfer betweenresistive heater 1789 and lid 1710. Without heater 1789, cooling channel1791 could continuously remove heat from lid 1710. As a result, coolingchannel 1791 also affects the temperature of portions of lid 1710 incontact with precursor vapor, such as the area surrounding central borethrough 1794 and the gas box. While cooler lid 1710 temperatures improveconditions for o-ring 1770, cooler lid 1710 temperatures could result inundesired condensation of precursor vapor. Thus, it is to be appreciatedthat resistive heater 1789 is positioned to heat those portions of lid1710 in contact with the vaporized precursor flow such as the gas boxand the area surrounding central bore through 1794. As shown in FIG.17B, for example, heater 1789 is located between cooling channel 1719and central bore through 1794 while also positioned to provide heatingto the lid surface adjacent to blocker plate 1796.

Vapor Delivery System

Vapor delivery system 1708 provides a method and an apparatus forsupplying controlled, repeatable, vaporization of low vapor pressureprecursors for film deposition on a substrate 1701 located withinprocessing region 1772. One method provides for the direct injection ofvaporized TAETO and TAT-DMAE. One of ordinary skill will appreciate thespecific features detailed below which separately and when combinedallow vapor delivery system 1708 to vaporize and precisely control thedelivery of liquid precursors including those precursors having vaporpressures significantly lower than precursors utilized in prior artvapor delivery system or, specifically, precursors having vaporpressures below about 10 Torr at 1 atm and 100° C. (FIG. 1).

The various components of vapor delivery system 1708 are placed in closeproximity to chamber 1702 in order to minimize the length of temperaturecontrolled vapor passageways between the outlet of vaporizer 1752 andprocessing region 1772. Even though practice in the semiconductorprocessing arts is to place vapor systems remotely from processingchambers to either ensure serviceability or reduce the amount ofcleanroom space occupied by a processing system, vapor delivery system1708 of the present invention utilizes an innovative compact designwhich allows all system components—less bulk liquid precursor, carriergas and process gas supplies—to be located directly adjacent to chamber1702 in close proximity to precursor and process gas chamber feedthroughs.

A low vapor pressure liquid precursor, such as TAT-DMAE or TAETO, can bestored in bulk storage container 1756 located remotely or on mainframesupport in proximity to processing chamber 1702. Liquid precursor storedin tank 1756 is maintained under pressure of an inert gas such as Heliumat about 15 to 70 psig. The gas pressure within tank 1756 providessufficient pressure on the liquid precursor such that liquid precursorflows to other vapor delivery system components thus removing the needfor a pump to deliver the liquid precursor. The outlet of delivery tank1756 is provided with a shut-off valve (not shown) to isolate bulk tank1756 for maintenance or replenishment of the liquid precursor. As aresult of the pressure head on tank 1756, liquid precursor from tank1756 is provided to liquid supply line and the precursor inlet ofprecursor/solvent inlet valve 1754. When aligned for liquid precursor,precursor/solvent valve 1754 provides liquid precursor toprecursor/solvent outlet and into precursor/solvent supply line toliquid flow meter inlet. Liquid flow meter 1750 measures precursor flowrate and provides via liquid flow meter outlet 511 liquid precursor tovaporize supply line 1763 and then to vaporized inlet. Vaporizer 1752 inconjunction with a heated carrier gas (described below) converts theliquid precursor into precursor vapor. A carrier gas, such as nitrogenor helium, is supplied into carrier gas heat exchanger inlet 1761 at apressure of about 15 psi. Carrier gas heat exchanger 1760 is a gas toresistive heater type heat exchanger like Model HX-01 commerciallyavailable from Lintec. Carrier gas heat exchanger 1760 preheats thecarrier gas to a temperature such that the heated carrier gas streamentering vaporizer 1752 does not interfere with the efficientvaporization of the precursor liquid undergoing vaporization withinvaporizer 1752. Heated carrier gas is provided to vaporizer 1752 viacarrier gas supply line 1764 and carrier gas inlet to vaporizer. Theheated carrier gas should not be heated uncontrollably since a carriergas heated above the decomposition temperature of the precursorundergoing vaporization could result in precursor decomposition withinvaporizer 1752. Thus, carrier gas heat exchanger 1760 should heat thecarrier gas into a temperature range bounded by, at the lower limit, thecondensation temperature of the precursor and, at the upper limit, thedecomposition temperature of the precursor. For a tantalum precursorsuch as TAT-DMAE for example, a representative vaporization temperatureis about 130° C. and a decomposition temperature is about 190° C. Atypical carrier gas such as nitrogen could be provided to a vaporizer1752, which is vaporizing a tantalum precursor such as TAT-DMAE, atabout between 200 and 2000 standard cubic centimeters per minute (sccm)and a temperature of about between 130° C. and 160° C. These conditionsresult in a vaporized precursor flow rate in the range of about 10-50milligrams per minute. Carrier gas temperature can also be such that thetemperature of the carrier gas entering vaporizer 1752 is at least ashigh if not higher than the vaporization temperature of the precursorbeing vaporized in vaporizer 1752. Of particular concern is theprevention of precursor vapor condensation within the small diameterconduits which exist within vaporizer 1752. As such, carrier gastemperatures below vaporization conditions within vaporizer 1752 couldsufficiently cool the vaporized precursor, result in condensation andshould therefore be avoided.

The Remote Plasma Generator

Another aspect of the processing apparatus 1760 of the present inventionis remote plasma apparatus 1706 shown FIG. 17C in relation to centralsubstrate transfer chamber 1224 and chamber 1702 and components ofheated exhaust system 1705. Remote plasma apparatus 1706 creates aplasma outside of or remote to processing region 1772 for cleaning,deposition, annealing or other processes within processing region 1772.One advantage of a remote plasma generator 1706 is that the generatedplasma or activated species created by remote plasma generator 1706 maybe used for cleaning or process applications within the processingregion without subjecting internal chamber components such as substratesupport 1776 or showerhead 1774 to plasma attack which usually resultswhen conventional RF energy is applied within process region 1772 tocreate a plasma. Several components of remote plasma apparatus 1706 arevisible in FIG. 17C such as magnetron 1744, auto tuner controller 1746,isolator 1741, auto tuner 1748, adapter tube 1745 and adapter tube heatinsulation disc 1747.

Magnetron assembly 1744 houses the magnetron tube, which produces themicrowave energy. The magnetron tube consists of a hot filamentcylindrical cathode surrounded by an anode with a van array. Thisanode/cathode assembly produces a strong magnetic field when it issupplied with DC power from a power supply. Electrons coming intocontact with this magnetic field follow a circular path as they travelbetween the anode and the cathode. This circular motion induces voltageresonance, or microwaves, between the anode vanes. An antenna channelsthe microwaves from magnetron 1744 to isolator 1741 and wave guide 1749.Isolator 1741 absorbs and dissipates reflected power to prevent damageto magnetron 1744. Wave guide 1749 channels microwave from isolator 1741into auto tuner 1748.

Auto tuner 1748 matches the impedance of magnetron 1744 and microwavecavity 1743 to achieve the maximum degree of reflected power byadjusting the vertical position of three tuning stubs located insidewave guide 1749. Auto tuner 1748 also supplies a feedback signal to themagnetron power supply in order to continuously match the actual forwardpower to the setpoint. Auto tuner controller 1746 controls the positionof the tuning stubs within wave guide 1749 to minimize reflected power.Auto tuner controller 1746 also displays the position of the stubs aswell as forward and reflect power readings.

Microwave applicator cavity 1743 is where gas or gases supplied via gassupply inlet 1739 are ionized. Gas supplied via gas supply inlet 1739enters a water cooled quartz or sapphire tube within microwaveapplicator 1743, is subjected to microwaves and ionizes producingactivated species which can then be used in cleaning and processingoperations within processing region 1772. One such cleaning gas is NF3which can be used to supply activated flourine for cleaning processingregion 1772 when a substrate 1701 is not present in processing region202. Activated species can also be used to anneal or otherwise processsemiconductor or other materials present on a substrate 1701 positionedwithin processing region 1772. An optical plasma sensor 1737 detects theexistence of plasma within cavity 1743. Activated species generatedwithin microwaves applicator cavity 1743 are supplied to activatespecies chamber feed through 1735 via adapter tub 1745. Adapter tube1745 is insulated from the elevated temperature of chamber body 1712 byadapter tube isolation disc 1747.

From activated species chamber feed through 1739, the activated speciespass through lid bore-through and enter activated species inlet block1740 which, together with activated species block 1742, provide ano-ring sealed, air tight conduit i.e., activated species conduit 1790,between lid bore-through and central gas feed-through 1792 withincentral mixing block 1718.

Method of Using Clean/Gate Tool 1200

Clean/Gate Tool 1200 can be used to form a dielectric film and electrodeon a substrate. For example, as illustrated in FIGS. 15A-15D, theclean/gate tool 1200 can wet clean a substrate, monitor the quality ofthe wet clean, grow a high quality gate dielectric on the substrate, andthen deposit a polysilicon gate film on the dielectric and then measurethe thickness of the deposited gate film. A similar process can be usedin Clean/Gate Tool 1200 to form a capacitor dielectric and capacitorelectrode on a substrate.

According to an embodiment of the present invention, a substrate orwafer, such as wafer 1500, shown in FIG. 15A is brought to clean/gatetool 1200 in a FOUP 1220 which is loaded onto Clean/Gate Tool 1200.Wafer 1500 will typically include a thin sacrificial oxide or nativeoxide 1504 formed on a doped monocrystalline silicon substrate 1502 (ora silicon epitaxial film). Generally, contaminants, such as particles1506, will be present in and/or on sacrificial oxide 1504. First, accessdoor 1121 is opened (as is the adjacent door on FOUP 1220). Robot 1212then removes wafer 1500 from FOUP 1220 and brings it into atmospherictransfer chamber 1210, and then inserts wafer 1500 into clean module 200where it is held by support 210.

Next, wafer 1500 is exposed to a wet etchant for a sufficient period oftime to etch or strip away all or a portion of sacrificial oxide 1504. Asacrificial oxide film can be etched away by exposing it to a dilute HFsolution, such as a 500:1 to 10:1 DI H₂O:HF solution. The concentrationand/or etch time will typically depend upon the thickness of thesacrificial film and the amount of the film to be removed.

Directly after etching sacrificial oxide 1504, wafer 1500 is wet cleanedin module 200. Wafer 1500 can be cleaned in module 200 as describedabove. In an embodiment of the present invention, wafer 1500 is cleanedwith a single solution containing NH₄OH, H₂O₂, a chelating agent, and asurfactant. In another embodiment of the present invention, wafer 1500is cleaned by standard RCA cleaning solutions (SC1 and SC2). Aftersufficient cleaning, as shown in FIG. 15B, wafer 1500 is dried in module200.

Wafer 1500 is then removed by robot 1212 from clean module 200 andbrought into atmospheric transfer chamber 1210. The wafer is then, ifdesired, transferred into either i) integrated particle monitoring tool300 or ii) into integrated thickness measuring module 1290. Wafer 1500can be brought into integrated thickness monitoring module 1290 in orderto measure the remaining thickness of the sacrificial oxide 1504 todetermine if either to much, to little or the correct amount of film hasbeen removed. If too little film 1504 has been removed, wafer 1500 canbe removed from module 1600 and placed back into wet clean module 200 inorder to further etch the sacrificial film 1506. The amount ofadditional etching required, as determined in thickness measuring module1290, can be used to determine or control the process parameters, suchas HF concentration, etch time and rotation rate, of the second etchingof sacrificial film 1506 to ensure that the required amount ofsacrificial oxide 1506 is removed. If too much film 1506 has beenremoved, then wafer 1500 can be removed from module 1600 and transferredout of Clean/Gate Tool 1200 through atmospheric transfer chamber 1210for further rework. If the correct amount of film has been removed, thenwafer 1500 can be removed from integrated thickness module 1290 by robot1212 and transferred into integrated particle monitoring module 300, ifdesired.

In integrated particle monitoring tool 300, the surface of wafer 1500,as shown in FIG. 15B, can be scanned and mapped to determine if thesurface has been sufficiently cleaned of contaminants 1506. If thesurface has not been sufficiently cleaned, wafer 1500 can be removedfrom the integrated particle monitoring module 300 and sent back toclean module 200 for further cleaning. The amount and type of a secondcleaning of wafer 1500 can be determined by the information receivedduring the integrated particle monitoring of wafer 1500.

If wafer 1500 has been sufficiently cleaned, then wafer 1500 is removedfrom the integrated particle monitoring tool 300 and brought into theatmospheric transfer chamber 1210 to begin further processing in thesub-atmospheric portion 1204 of Clean/Gate Tool 1200.

It is to be appreciated that a wafer can be brought into either onlyintegrated particle monitoring tool 300 and not thickness monitoringtool 1700 or can be brought into only thickness monitoring tool 1600 andnot integrated particle monitoring tool 300, if desired. Additionally,if desired, a wafer can be brought into integrated particle monitoring300 for process prior to bringing it into integrated thicknessmonitoring tool 1600 for processing. Additionally, it is to beappreciated that every wafer need not necessarily be measured forthickness and/or particles. If desired, one can utilize spot checks, offor example every ten wafers, to determine whether or not proper etchinghas occurred and/or particles have been removed. In this case theinformation from the integrated particle monitor tool and/or theintegrated thickness monitor tool 1700 can be used to adjust the stripand cleaning recipe for the next 10 wafers.

After wafer 1500 has been sufficiently etched and cleaned, as shown inFIG. 15B, door 1205 is opened and wafer 1500 transferred fromatmospheric transfer chamber 1210 into load lock 1206 by robot 1212.Door 1205 is then sealed and load lock 1206 evacuated to the pressurewithin sub-atmospheric transfer chamber 1224. Next, door 1207 is openedand wafer handling device 1226 removes wafer 1500 from load lock 1206and brings it into sub-atmospheric transfer chamber 1224. Next, wafer1500 is brought into thermal oxidation chamber 1300 and placed onsupport 1362 by wafer handling device 1226. Next, a silicon dioxidedielectric film 1508 is grown on monocrystalline silicon substrate 1502as shown in FIG. 15C. If desired, a nitrogen containing gas or aremotely generated nitrogen plasma can be inserted into chamber 1313during film growth to form a silicon oxide containing nitrogen 1510 or asilicon oxynitride film. It is to be appreciated that a siliconoxynitride film has a higher dielectric constant than does a silicondioxide film.

In order to grow a dielectric film on wafer 1500, chamber 1313 is sealedand the pressure reduced to less than the sub-atmospheric transferchamber pressure of approximately 20 Torr. Chamber 1313 is evacuated toa pressure to sufficiently remove the nitrogen ambient, typicallynitrogen, in chamber 1313. Chamber 13 is pumped down to a prereactionpressure less than the pressure at which the insitu moisture generationis to occur, and is preferably pumped down to a pressure of less than 1torr.

Simultaneous with the prereaction pump down, power is applied to lamps1319 which in turn irradiate wafer 1500 and silicon carbide support ring1362 and thereby heat wafer 1500 and support ring 1362 to astabilization temperature. The stabilization temperature of wafer 1500is less than the temperature (reaction temperature) required to initiatethe reaction of the hydrogen containing gas and oxygen containing gas tobe utilized for the insitu moisture generation. The stabilizationtemperature in the preferred embodiment of the present invention isapproximately 500° C.

Once the stabilization temperature and the prereaction pressure arereached, chamber 1313 is backfilled with the desired mixture of processgas. The process gas includes a reactant gas mixture comprising tworeactant gasses: a hydrogen containing gas and an oxygen containing gas,which can be reacted together to form water vapor (H₂O) at temperaturesbetween 400-1250° C. The hydrogen containing gas, is preferably hydrogengas (H₂), but may be other hydrogen containing gasses such as, but notlimited to, ammonia (NH₃), deuterium (heavy hydrogen) and hydrocarbonssuch as methane (CH₄). The oxygen containing gas is preferably oxygengas (O₂) but may be other types of oxygen containing gases such as butnot limited to nitrous oxide (N₂O). Other gasses, such as but notlimited to nitrogen (N₂), may be included in the process gas mix ifdesired. The oxygen containing gas and the hydrogen containing gas arepreferably mixed together in chamber 1313 to form the reactant gasmixture.

In the present invention the partial pressure of the reactant gasmixture (i.e., the combined partial pressure of the hydrogen containinggas and the oxygen containing gas) is controlled to ensure safe reactionconditions. According to the present invention, chamber 1313 isbackfilled with process gas such that the partial pressure of thereactant gas mixture is less than the partial pressure at whichspontaneous combustion of the entire volume of the desired concentrationratio of reactant gas will not produce a detonation pressure wave of apredetermined amount. The predetermined amount is the amount of pressurethat chamber 1313 can reliably handle without failing.

According to the present invention, insitu moisture generation ispreferably carried out in a reaction chamber that can reliably handle adetonation pressure wave of four atmospheres or more without affectingits integrity. In such a case, reactant gas concentrations and operatingpartial pressure preferably do not provide a detonation wave greaterthan two atmospheres for the spontaneous combustion of the entire volumeof the chamber.

By controlling the chamber partial pressure of the reactant gas mixturein the present invention any concentration ratio of hydrogen containinggas and oxygen containing gas can be used including hydrogen richmixtures utilizing H2/O2 ratios greater than 2:1, respectively, andoxygen rich mixtures using H₂/O₂ ratios less than 0.5:1, respectively.For example, any concentration ratio of O₂ and H₂ can be safely used aslong as the chamber partial pressure of the reactant gasses ismaintained at less than 150 Torr at process temperature. The ability touse any concentration ratio of oxygen containing gas and hydrogencontaining gas enables one to produce an ambient with any desiredconcentration ratio of H₂/H₂O or any concentration ratio of O₂/H₂Odesired. Whether the ambient is oxygen rich or dilute steam or hydrogenrich or dilute steam can greatly affect device electricalcharacteristics of the deposited film 1510. The present inventionenables a wide variety of different steam ambients to be produced andtherefore a wide variety of different oxidation processes to beimplemented.

In some oxidation processes, an ambient having a low steam concentrationwith the balance O₂ may be desired. Such an ambient can be formed byutilizing a reactant gas mixture comprising 10% H₂ and 90% O₂. In otherprocesses, an ambient of hydrogen rich steam (70-80% H₂/30-20% H₂O) maybe desired. A hydrogen rich, low steam concentration ambient can beproduced according to the present invention by utilizing a reactive gasmix comprising between 5-20% O₂ with the remainder H₂ (95-80%). It is tobe appreciated that in the present invention any ratio of hydrogencontaining gas and oxygen containing gas may be utilized because theheated wafer provides a continual ignition source to drive the reaction.Unlike pyrogenic torch methods, the present invention is not restrictedto specific gas ratios necessary to keep a stable flame burning.

Next, power to lamps 1319 is increased so as to ramp up the temperatureof wafer 61 to process temperature. Wafer 61 is preferably ramped fromthe stabilization temperature to process temperature at a rate ofbetween 10-100° C./sec with 50° C./sec being preferred. The preferredprocess temperature of the present invention is between 600-1150° C.with 950° C. being preferred. The process temperature must be at leastthe reaction temperature (i.e., must be at least the temperature atwhich the reaction between the oxygen containing gas and the hydrogencontaining gas can be initiated by wafer 1500) which is typically atleast 600° C. It is to be noted that the actual reaction temperaturedepends upon the partial pressure of the reactant gas mixture as well ason the concentration ratio of the reactant gas mixture, and can bebetween 400° C. to 1250° C.

As the temperature of wafer 1500 is ramped up to process temperature, itpasses through the reaction temperature and causes the reaction of thehydrogen containing gas and the oxygen containing gas to form moistureor steam (H₂O). Since rapid thermal heating apparatus 1300 is a “coldwall” reactor, the only sufficiently hot surfaces in chamber 1313 toinitiate the reaction is the wafer 1500 and support ring 1362. As such,in the present invention the moisture generating reaction occurs near,about 1 cm from, the surface of wafer 1500. In the present invention themoisture generating reaction is confined to within about two inches ofthe wafer or about the amount at which support ring 1362 extends pastthe outside edge of wafer 1500. Since it is the temperature of the wafer(and support ring) which initiates or turns “on” the moisture generationreaction, the reaction is said to be thermally controlled by thetemperature of wafer 1500 (and support ring 1362). Additionally, thevapor generation reaction of the present invention is said to be“surface catalyzed” because the heated surface of the wafer is necessaryfor the reaction to occur, however, it is not consumed in the reactionwhich forms the water vapor.

Next, once the desired process temperature has been reached, thetemperature of wafer 1500 is held constant for a sufficient period oftime to enable the water vapor generated from the reaction of thehydrogen containing gas and the oxygen containing gas to oxidize siliconsurfaces or films to form SiO₂. Wafer 1500 will typically be held atprocess temperature for between 30-120 seconds. Process time andtemperature are generally dictated by the thickness of the oxide filmdesired, the purpose of the oxidation, and the type and concentrationsof the process gasses. FIG. 15C illustrates an oxide 1508 formed onwafer 1500 by oxidation of silicon surfaces 1502 by water vapor (H₂O)generated by the insitu moisture generation process. It is to beappreciated that the process temperature must be sufficient to enablethe reaction of the generated water vapor or steam with silicon surfacesto form silicon dioxide.

Next, power to lamps 1319 is reduced or turned off to reduce thetemperature of wafer 1500. The temperature of wafer 1500 decreases(ramps down) as fast as it is able to cool down (at about 50° C./sec.).Simultaneously, N2 purge gas is fed into the chamber 1313. The moisturegeneration reaction ceases when wafer 1500 and support ring 1362 dropbelow the reaction temperature. Again it is the wafer temperature (andsupport ring) which dictates when the moisture reaction is turned “on”or “off”.

Next, chamber 1313 is pumped down, preferably below 1 torr, to ensurethat no residual oxygen containing gas and hydrogen containing gas arepresent in chamber 1313. The chamber is then backfilled with N₂ gas tothe transfer pressure in sub-atmospheric transfer chamber 1224, ofapproximately 20 torr and wafer 1500 transferred out of chamber 1313 tocomplete the process.

At times it may be desirable to utilize concentration ratios of hydrogencontaining gas and oxygen containing gas which will produce an ambientwith a large concentration of water vapor (e.g., >40% H₂O). Such anambient can be formed with a reactant gas mixture, for example,comprising 40-80% H₂/60-20% O₂. A gas mixture near the stoichiometricratio may yield too much combustible material to enable safe reactionconditions. In such a situation, a low concentration gas mixture (e.g.,less than 15% O₂ in H₂) can be provided into the reaction chamber duringstep 306, the wafer temperature raised to the reaction temperature instep 308, and the reaction initiated with the lower concentration ratio.Once the reaction has been initiated and the existing reactant gasvolume begins to deplete, the concentration ratio can be increased tothe desired level. In this way, the amount of fuel available at thestart of the reaction is kept small and safe operating conditionsassured.

In an embodiment of the present invention a relatively low, reactive gaspartial pressure is used for insitu steam generation in order to obtainenhanced oxidation rates. It has been found that providing a partialpressure of between 1 Torr to 50 Torr of hydrogen gas (H₂) and oxygengas (O₂) that an enhanced oxide growth rate of silicon can be achieved.That is, for a given set of process conditions (i.e., H₂/O₂concentration ratio, temperature, and flow rate) the oxidation rate ofsilicon is actually higher for lower partial pressures (1-50 Torr) of H₂and O₂ than for higher partial pressures (i.e., from 50 Torr to 100Torr).

After a sufficient dielectric film 1508 has been grown onmonocrystalline silicon substrate 1502, as shown in FIG. 15C, wafer 1500is removed from thermal oxidation chamber 1300 by robot 1226. In anembodiment of the present invention, wafer 1500 is transferred by robot1226 through sub-atmospheric transfer chamber 1224 and placed into highk dielectric module 1700 to deposit a high k metal oxide dielectric film1511 on silicon oxide film 1508 or a silicon oxide film containingnitrogen 1510. In an embodiment of the present invention the dielectricfilm 1511 is a transition metal dielectric film such as, but not limitedto, tantalum pentaoxide (Ta₂O₅) and titanium oxide (TiO₂). In anotherembodiment dielectric layer 1511 is a tantalum pentaoxide film dopedwith titanium. Additionally dielectric layer 1511 can be a compositedielectric film comprising a stack of different dielectric films such asa Ta₂O₅/TiO₂/Ta₂O₅ stacked dielectric film. Additionally, dielectriclayer 208 can be a piezoelectric dielectric such as Barium StrontiumTitanate (BST) and Lead Zirconium Titanate (PZT) or a ferroelectric.

In order to form a dielectric layer 1511 onto wafer 1500, the substratecan be placed onto support 1776 in chamber 1702 of high k module 1700.The wafer 1500 is then heated to a desired deposition temperature whilethe pressure within the chamber is pumped down (reduced) to a desireddeposition pressure. Deposition gases are then fed into the chamber anda dielectric layer formed therefrom.

To blanket deposit a tantalum pentaoxide (Ta₂O₅) dielectric film bythermal chemical vapor deposition a deposition gas mix comprising, asource of tantalum, such as but not limited to, TAETO [Ta (OC₂H₅)₅] andTAT-DMAE [Ta (OC₂H₅)₄ (OCHCH₂N(CH₃)₂], and source of oxygen such as O₂or N₂O can be fed into a deposition chamber while the substrate isheated to a deposition temperature of between 300-500° C. and thechamber maintained at a deposition pressure of between 0.5-10 Torr. Theflow of deposition gas over the heated substrate results in thermaldecomposition of the metal organic Ta-containing precursor andsubsequent deposition of a tantalum pentaoxide film. In one embodimentTAETO or TAT-DMAE is fed into the chamber at a rate of between 10-50milligrams per minute while O₂ or N₂O is fed into the chamber at a rateof 0.3-1.0 SLM. TAETO and TAT-DMAE can be provided by direct liquidinjection or vaporized with a bubbler prior to entering the depositionchamber. A carrier gas, such as N₂, H₂ and He, at a rate of between0.5-2.0 SLM can be used to transport the vaporized TAETO or TAT-DMAEliquid into the deposition chamber 1702. Deposition is continued until adielectric film 1511 of a desired thickness is formed. A tantalumpentaoxide (Ta₂O₅) dielectric film having a thickness between 50-200 Åprovides a suitable dielectric film.

It has been found that the use of nitrous oxide (N₂O) as the oxidizer(source of oxygen), as opposed to oxygen gas O₂ improves the electricalproperties of the deposited tantalum pentaoxide (Ta₂O₅) dielectric filmduring deposition. The use of N₂O, as opposed to O₂, has been found toreduce the leakage current and enhance the capacitance of fabricatedcapacitors. The inclusion of N₂O as an oxidizer aids in the removal ofcarbon from the film during growth which helps to improve the quality ofthe film.

In an embodiment of the present invention dielectric layer 1511 is atantalum pentaoxide (Ta₂O₅) film doped with titanium (Ti). A tantalumpentaoxide film doped with titanium can be formed by thermal chemicalvapor deposition by providing a source of titanium, such as but notlimited to TIPT (C₁₂H₂₆O₄Ti), into the process chamber while forming atantalum pentaoxide film as described above. TIPT diluted byapproximately 50% with a suitable solvent such as isopropyl alcohol(EPA) can be fed into the process chamber by direct liquid injection orthrough the use of a bubbler and carrier gas such as N₂. A TIPT dilutedflow rate of between 5-20 mg/minute can be used to produce a tantalumpentaoxide film having a titanium doping density of between 5-20 atomicpercent and a dielectric constant between 20-40. The precise Ti dopingdensity can be controlled by varying the tantalum source flow raterelative to the titanium source flow rate. It is to be appreciated thata tantalum pentaoxide film doped with titanium atoms exhibits a higherdielectric constant than an undoped tantalum pentaoxide film.

In another embodiment of the present invention dielectric layer 1511 isa composite dielectric layer comprising a stack of different dielectricmaterials such as a Ta₂O₅/TiO₂/Ta₂O₅ stack. A Ta₂O₅/TiO₂/Ta₂O₅ compositefilm can be formed by first depositing a tantalum pentaoxide film asdescribed above. After depositing a tantalum pentaoxide film having athickness between 20-50 Å the flow of the tantalum source is stopped andreplaced with a flow of a source of titanium, such as TIPT, at a dilutedflow rate of between 5-20 mg/min. After depositing a titanium oxide filmhaving a thickness of between 20-50 Å, the titanium source is replacedwith the tantalum source and the deposition continued to form a secondtantalum pentaoxide film having a thickness of between 20-50 Å. Bysandwiching a higher dielectric constant titanium oxide (TiO₂) filmbetween two tantalum pentaoxide (Ta₂O₅) films, the dielectric constantof a composite stack is increased over that of a homogeneous layer oftantalum pentaoxide (Ta₂O₅).

Next, dielectric film 1511 is annealed with remotely generated activeatomic species to form an annealed dielectric layer 1511. Dielectricfilm 1511 can be annealed in chamber 1702 coupled to remote plasmagenerator 1706. Substrate 1500 is then heated to an anneal temperatureand exposed to active atomic species generated by disassociating ananneal gas in application cavity 1743. By generating the active atomicspecies in an application cavity 1743 chamber remote from chamber 1702(the chamber in which the substrate is situated) a low temperatureanneal can be accomplished without exposing the substrate to the harmfulplasma used to form the active atomic species. With the process andapparatus of the present invention anneal temperatures of less than 400°C. can be used. The use of remotely generated active atomic species toanneal dielectric film 1511 enables anneal temperatures of less than orequal to the deposition temperature of the dielectric film to be used.

In one embodiment of the present invention dielectric film 1511 is atransition metal dielectric and is annealed with reactive oxygen atomsformed by remotely disassociating O₂ gas. Dielectric layer 1511 can beannealed in chamber 1702 with a reactive oxygen atoms created byproviding an anneal gas comprising two SLM of O₂ and one SLM of N2 intochamber application cavity 1743, and applying a power between 500-1500Watts to magnetron 302 to generate microwaves which cause a plasma toignite from the anneal gas. Alternatively, reactive oxygen atoms can beformed by flowing an anneal gas comprising two SLM of O₂ and three SLMof argon (Ar) into cavity 1743. While reactive oxygen atoms are fed intoanneal chamber 1702, substrate 200 is heated to a temperature ofapproximately 300° C. and chamber 1702 maintained at an anneal pressureof approximately 2 Torr, High K Dielectric layer 1511 can besufficiently annealed by exposing substrate 200 to reactive oxygen atomsfor between 30-120 seconds.

An inert gas, such as N₂ or argon (Ar), is preferably included in theanneal gas stream in order to help prevent recombination of the activeatomic species. It is to be noted that as the active atomic species(e.g. reactive oxygen atoms) travel from the application cavity 1743 tochamber 1702, they collide with one another and recombine to form O₂molecules. By including an inert gas, in the anneal gas mix, the inertgas does not disassociate and so provides atoms which the active atomicspecies can collide into without recombining. Additionally, in order tohelp prevent recombination of the active atomic species, it is advisableto keep the distance between application cavity 1743 and chamber 1702 asshort as possible.

Annealing a transition-metal dielectric film 1511 with reactive oxygenatoms fills oxygen vacancies (satisfies sites) in the dielectric film1511 which greatly reduces the leakage of the film. Additionally,annealing transition metal dielectric 1511 helps to remove carbon (C) inthe film which can contribute to leakage. Carbon can be incorporatedinto transition metal dielectrics because the tantalum and titaniumsources, TAT-DMAE, TAETO, and TIPT are carbon containing compounds. Thereactive oxygen atoms remove carbon from the film by reacting withcarbon and forming carbon dioxide (CO₂) vapor which can then beexhausted out from the chamber. Next, a doped or undoped polycrystallinesilicon film or other gate material is deposited onto the gatedielectric layer 1508 (or high k dielectric 1511, if used), as shown inFIG. 15D.

In order to deposit a polysilicon film 1512 the desired depositionpressure and temperature are obtained and stabilized in chamber 1490.While achieving pressure and temperature stabilization, a stabilizationgas such as N₂, He, Ar, H₂ or combinations thereof are fed into chamber1490. In a preferred embodiment of the present invention the flow andconcentration of the dilution gas used in the subsequent polysilicondeposition is used to achieve temperature and pressure stabilization.Using the dilution gas for stabilization enables the dilution gas flowand concentrations to stabilize prior to polysilicon deposition.

In an embodiment of the present invention the chamber is evacuated to apressure between 150-350 Torr with 200-275 Torr being preferred and theheater temperature raised to between 700-740° C. and preferably between710-720° C. while the dilution gas is fed into chamber 1490 at a flowrate between 10-30 slm. According to the present invention the dilutiongas consist of H₂ and an inert gas, such as but not limited to nitrogen(N₂), argon (Ar), and helium (He), and combinations thereof. For thepurpose of the present invention an inert gas is a gas which is notconsumed by or which does not interact with the reaction used to depositthe polysilicon film and does not interact with chamber componentsduring polysilicon film deposition. In a preferred embodiment of thepresent invention the inert gas consists only of nitrogen (N₂). In anembodiment of the present invention H₂ comprises more than 8% and lessthan 20% by volume of the dilution gas mix with the dilution gas mixpreferably having between 10-15% H₂ by volume.

In the present invention the dilution gas mix has a sufficient H₂/inertgas concentration ratio such that a subsequently deposited polysiliconfilm is dominated by the <111> crystal orientation as compared to the<220> crystal orientation. Additionally, the dilution gas mix has asufficient H₂/inert gas concentration ratio so that the subsequentlydeposited polycrystalline silicon film has a random grain structure withan average grain size between 50-500 Å.

In an embodiment of the present invention the dilution gas mix issupplied into chamber 1490 in two separate components. A first componentof the dilution gas mix is fed through distribution port 1420 in chamberlid 1430. The first component consist of all the H₂ used in the dilutiongas mix and a portion (typically about ⅔) of the inert gas used in thedilution gas mix. The second component of the dilution gas mix is fedinto the lower portion of chamber 1490 beneath heater 1480 and consistsof the remaining portion (typically about ⅓) of the inert gas used inthe dilution gas mix. The purpose of providing some of the inert gasthrough the bottom chamber portion is to help prevent thepolycrystalline silicon film from depositing on components in the lowerportion of the chamber. In the embodiment of the present inventionbetween 8-18 slm with about 9 slm being preferred of an inert gas(preferably N₂) is fed through the top distribution plate 1420 whilebetween 3-10 slm, with 4-6 slm being preferred, of the inert gas(preferably N₂) is fed into the bottom or lower portion of chamber 1490.The desired percentage of H₂ in the dilution gas mix is mixed with theinert gas prior to entering distribution port 1420.

Next, once the temperature, pressure, and gas flows have been stabilizeda process gas mix comprising a silicon source gas and a dilution gas mixcomprising H₂ and an inert gas is fed into chamber 1490 to deposit apolycrystalline silicon film 1512 on substrate 1500 as shown in FIG.15D. In the preferred embodiment of the present invention the siliconsource gas is silane (SiH₄) but can be other silicon source gases suchas disilane (Si₂H₆). According to the preferred embodiment of thepresent invention between 50-150 sccm, with between 70-100 sccm beingpreferred, of silane (SiH₄) is added to the dilution gas mix alreadyflowing and stabilized during the temperature and pressure stabilizationstep. In this way during the deposition of polysilicon, a process gasmix comprising between 50-150 sccm of silane (SiH₄) and between 10-30slm of dilution gas mix comprising H₂ and an inert gas is fed into thechamber while the pressure in chamber 1490 is maintained between 150-350Torr and the temperature of susceptor 1405 is maintained between700-740° C. (It is to be appreciated that in the LPCVD reactor 1400 thetemperature of the substrate or wafer 1500 is typically about 50°(cooler than the measured temperature of susceptor 1405). In thepreferred embodiment of the present invention the silicon source gas isadded to the first component (upper component) of the dilution gas mixand flows into chamber 1490 through inlet port 1420. If desired, adopant gas source, such as but not limited to diborane and phosphine canbe included in the process gas mix to insitu dope the polysilicon film.

The thermal energy from susceptor 1405 and wafer 1500 causes the siliconsource gas to thermally decompose and deposit a polysilicon film on gatedielectric 1508 on silicon substrate 1502 as shown in FIG. 15D. In anembodiment of the present invention only thermal energy is used todecompose the silicon source gas without the aid of additional energysources such as plasma or photon enhancement.

As process gas mix is fed into chamber 1490, the silicon source gasdecomposes to provide silicon atoms which in turn form a polycrystallinesilicon film on insulating layer 1508. It is to be appreciated that H₂is a reaction product of the decomposition of silane (SiH₄). By adding asuitable amount of H₂ in the process gas mix the decomposition of silane(SiH₄) is slowed which enables a polycrystalline silicon film 1512 to beformed with small and random grains. In the present invention H₂ is usedto manipulate the silicon resource reaction across the wafer. By havingH₂ comprise between 8-20% of the dilution gas mix random grains havingan average grain size between 50-500 Å can be formed. Additionally, byincluding a sufficient amount of H₂ in the dilution gas mix apolycrystalline silicon film 506 which is dominated by the <111> crystalorientation, as opposed to the <220> crystal orientation is formed.

According to the present invention the deposition pressure, temperature,and process gas flow rates and concentration are chosen so that apolysilicon film is deposited at a rate between 1500-5000 Å per minutewith between 2000-300 Å per minute being preferred. The process gas mixis continually fed into chamber 1490 until a polysilicon film 1512 of adesired thickness is formed. For gate electrode applications apolysilicon film 1512 having a thickness between 500-2000 Å has beenfound suitable.

After completing the deposition polysilicon film 1512, heater 1480 islowered from the process position to the load position and wafer 500removed from chamber 1490 by robot 1226.

Door 1211 is then opened and then wafer 1500 placed into load lock 1208and door 1211 sealed. Next, the pressure within load lock 1208 is raisedto the pressure within atmospheric transfer chamber 1210. The door 1209is then opened and robot 1212 removes wafer 1500 from load lock 1208. Atthis point, wafer 1500 can be i) placed into integrated thicknessmonitoring tool 1700 to measure the thickness of silicon film 1512; orii) can be placed into wet clean module 200 where it is exposed to acleaning solution comprising, for example, hydrofluoric acid in order toremove contaminants from wafer 1500, or iii) can be removed fromatmospheric transfer chamber 1210 by robot 1212 and placed into FOUP1222. At this time a method of forming a gate dielectric film 1508 and agate electrode film 1512 in Clean/Gate tool 1200 has been described.Further processing can be used to etch a gate electrode 1514 from film1512 and to form source/drain regions 1516 as well as spacers 1518 inorder to complete fabrication of a metal oxide semiconductor device asshown in FIG. 15E.

Photolithography Process Tool

FIG. 18A illustrates a photolithography processing tool 1800 which canbe used to clean a wafer, form a photoresist on the wafer and thenexpose the wafer in a closed and controlled environment.Photolithography process tool 1800 includes a single wafer wet cleanmodule, such as module 200 shown in FIG. 2A, a photoresist track 1802for applying, and exposing photoresist and a transfer chamber 1804having a wafer handling robot 1808 on a single linear track 1806contained therein. Wet clean station 200 and photoresist track 1802 areeach directly coupled to transfer chamber 1804 and are each accessibleby robot 1808. In an embodiment of the present invention the photoresisttrack 1802 includes a bake station 1810 for removing water from a waferto be photoresist coated, a photoresist application station 1812, suchas a spin station, whereby a desired amount of photoresist is spun on awafer, a soft bake station 1814 which removes solvent from the depositedphotoresist material, and an exposure tool, such as a stepper, where thedeposited photoresist is exposed to radiation, such as deep ultraviolet(DUV) radiation or extreme ultraviolet (EUV) radiation through a maskused to define a pattern within the photoresist layer.

Tool 1800 includes a filter 1820 coupled to transfer chamber 1804 forremoving amine and ammonia vapor from tool 1800. In an embodiment of thepresent invention, the ambient within tool 1800 is sufficiently void ofamine and ammonia vapor so that they do not affect the photoresistprocessing in tool 1800. Additionally, tool 1800 includes acomputer/controller 124 which controls the operation of robot 1808 aswell as the various operations which occur in clean module 200 andphotoresist track 1802. Additionally, photoresist tool 1800 can includea first FOUP 1822 coupled to a first side of transfer chamber 1804 forproviding wafers to tool 1800 through transfer chamber 1804. A secondFOUP 1824 can be included on the opposite end of transfer chamber 1806the FOUP 1822 for removing completed wafers from photolithographyprocess tool 1800.

In an embodiment of the present invention, as shown in FIG. 18B, aphotolithography process tool 1850 optionally includes a second wetclean chamber 200B positioned down stream of or after the photoresistdeposition module 1812 and positioned upstream or before the exposuremodule 1816. In this way, the backside of the wafer can be cleaned ofparticles after the photoresist has been deposited (or spun) and beforethe photoresist has been exposed.

Method of Operating Photolithography Process Tool

An example of the method of use of photolithography process tool 1800 isillustrated in FIGS. 19A-19G. In an embodiment of the present invention,a wafer 1900 is provided to photolithography process tool 1800 in a FOUP1822. Wafer 2000 has a frontside 1902 and a wafer backside 1904 oppositethe wafer frontside. Generally formed on the wafer frontside 1902 areplurality of small (less then 0.25 um) device features 1906, such asthin film lines used to form interconnects or electrodes. Wafer 1900typically include a plurality of particles 1908 undesirably formed onthe frontside and backside of the wafer 1900. In order tophotolithographically process wafer 1900, the door between transferchamber 1804 and FOUP 1822 is opened and wafer handling device 1808removes wafer 1900 from FOUP 1822 and brings it into transfer chamber1804. Robot 1808 then transfers the wafer into wet clean module 200where it is horizontally positioned by wafer support 210 parallel to andover a horizontally positioned plate 202 having a plurality of megasonictransducers 204 formed on the backside of the plate. The wafer ispositioned so that the wafer backside 1904 is parallel to and adjacentto and spaced-apart from megasonic plate 202. At this time, the backsideof the wafer is cleaned of particles 1908 by flowing a fluid, such as DIwater or a cleaning solution comprising, for example,ammonia/peroxide/water. The cleaning solution can include a chelatingagent and/or surfactants. While the liquid is flowing between thebackside of the wafer 1904 and plate 202, megasonic energy is applied bytransducers 204 to produce sonic waves in a direction perpendicular tothe backside of the wafer 1900. The wafer can be rotated by support 210while cleaning the wafer. In one embodiment of the present invention, nofluid is provided onto the frontside 1902 of wafer 1900 while cleaningthe backside so that a liquid film 222 (shown in FIG. 2A) is not formedon the wafer frontside. In this way, megasonic energy is not able totransfer into a fluid on the frontside and fragile device features 2006formed on the wafer frontside are not damaged.

However, in an alternative embodiment of the present invention whilecleaning the wafer backside, cleaning solution and/or DI water can beprovided onto the wafer frontside 1902 to form a thin coat 222 (as shownin FIG. 2A) in order to clean the wafer frontside. Once the waferbackside has been sufficiently cleaned of particles 1908 as shown inFIG. 19B, the cleaning is stopped and the wafer spun dry.

Next, robot 1808 removes the cleaned wafer 1900 from wet clean module200 and brings it into transfer chamber 1804 and then slides down track1806 to bake station 1810 where it places wafer 1902 into bake station1810. While in bake station 1810 wafer 1900 is heated to a temperatureof approximately 200° C. in a nitrogen ambient and at a reduced pressurein order to remove all water vapor from wafer 1900 as shown in FIG. 19C.Bake station 1810 can include a horizontally positioned hot plate onwhich the backside 1904 of wafer 1900 is situated. Next, after wafer1902 has been sufficiently baked to remove water residue, robot 1808removes the baked wafer 1902 from bake station 1810 and brings it intotransfer chamber 1804, slides down track 1806 to spin station 1812 andplaces wafer 1902 into spin station 1812. Spin station 1812 willtypically include a rotatable plate on which the wafer is situated andthe nozzle placed above for depositing a photoresist film thereon. Oncein spin station 1812, a photoresist film 1910 is formed on the waferfrontside 1902 as shown in FIG. 19D. Photoresist material is an organicphoto-sensitive material which is sensitive to radiation at a certainfrequency. Typically today, photoresist films which are sensitive todeep UV (ultraviolet) light are utilized. Additionally, if desired,adhesion promoter, such as HMDS maybe deposited onto wafer frontside1902 prior to applying photoresist film 1910.

Next, after sufficient amount of photoresist 1910 has been applied tothe wafer frontside 1902, the wafer can optionally be placed into asecond wet clean chamber 200B in order to remove particles 1908 whichmay have formed on the wafer backside during the wafer coating process.In such a case, the wafer 1900 having a photoresist film 1910 formed onthe wafer frontside, is then held by wafer support 210 horizontallyabove and parallel to a plate 206 as shown in FIG. 2A. The waferbackside 1904 is adjacent to the plate 202. A fluid is then transportedbetween the plate 1902 and the wafer backside 1904 in order to removeparticles 1908 which develop during the photoresist deposition process.The cleaning solution can include a chelating agent and/or surfactants.While the liquid is flowing between the backside of the wafer 1904 andplate 202, megasonic energy can be applied by transducers 204 to producesonic waves in a direction perpendicular to the backside of the wafer1900. The wafer can be rotated by support 210 while cleaning thebackside. During the backside cleaning of the wafer with the photoresistmaterials 1910 on the frontside, no solution is provided through nozzle214 to the wafer frontside 1902. That is, during the backside clean witha photoresist film on the frontside the frontside is kept completelydry. It is to be appreciated, that the photoresist film 1908 formed onthe wafer frontside is not to be exposed to cleaning solutions or DIwater during the wafer backside cleaning. In an embodiment of thepresent invention, clean air or an inert gas, such as N₂, can be blownonto the top surface of wafer 1900 while the backside 1904 is cleaned ofparticles to ensure that no backside cleaning solutions travel aroundthe edges of the wafer and wet or attack photoresist film 1910 on thewafer frontside 1902. After all of the particles 1912 have been removedfrom the wafer backside 1904 as shown in FIG. 19E, this optionalcleaning step can be stopped. Next, the robot 1808 removes wafer 1900from wet clean station 1900B and brings it into transfer chamber 1804.Robot 1808 then moves down track 1806 to soft bake station 1814 andplaces wafer 1900 with photoresist film 1910 into the soft bake station.(If backside cleaning with photoresist film 1910 is not to be used, thenthe wafer would be directly brought from the spin station into the softbake station 1814.) Once in soft bake station 1814 wafer 1900 is heatedto remove some of the solvents contained within photoresist film 1910 asshown in FIG. 19F.

After the wafer 1900 has been sufficiently soft baked in soft bakestation 1814, wafer 1900 is removed from soft bake station 1814 by robot1808 and robot 1808 travels down track 1806 to exposure station 1816 andplaces wafer 1900 in exposure station 1816. In exposure station 1816 thephotoresist film 1910 is exposed to radiation, such as DUV radiationfrom a light source 1914 which shines through a mask 1916 having apattern formed therein as shown in FIG. 19G. The mask 1916 blocks lightfrom exposing some portions of photoresist film 1910 and allows light toexpose other portions 1920 of photoresist mask 1910. The light radiationalters the chemical structure of the photoresist film to form lightexposed regions 1920 which can be selectively developed away withdeveloper from photoresist film 1910 which has not been exposed to light(1918). In this way, a photoresist mask can be formed on substrate 1900.An excellent exposure can take place because backside particles havebeen removed which could otherwise cause the image to be out of focus.Once sufficiently exposed, the robot 1808 removes exposed wafer 1900from exposure station 1816 and places it in FOUP 1824.

Shown in FIG. 18C is a photolithography processing apparatus inaccordance with an embodiment of the present invention. Photolithographyprocessing apparatus 1880 includes a photoresist application tool 1882,a single wafer backside cleaning tool 1884 and an exposure tool 1886.Single wafer backside cleaning tool 1884 is coupled between photoresistapplication tool 1882 and exposure tool 1886. Single wafer backsidecleaning tool 1884 can be said to be a buffer station in that it isdirectly coupled between photoresist application tool 1882 and exposuretool 1886. That is backside cleaning tool 1884 is directly coupled, byfor example bolts, to the output of photoresist application tool 1882and is directly coupled, by for example bolts, to the input of exposuretool 1886. In an embodiment photoresist application tool 1882, backsideclean tool 1884, and exposure tool 1886 each have their owncomputer/controller for separately controlling each of their operations.

The function of photoresist application tool 1882 is to form aphotoresist film (to subsequently be imaged) onto a wafer. Photoresistapplication tool 1882 can be any well-known photoresist application toolor track and in an embodiment it includes all stations necessary forpreparing a photoresist film for exposure in exposure tool 1886 In anembodiment of the present invention, photoresist application tool 1882includes a bake station 1810, a spin station 1812 and a soft bakestation 1814 as described above. Photoresist application tool 1882 has awafer handling robot 1888 for transferring wafers between the variousstations (e.g., between bake station 1810, spin station 1812, and softbake station 1814) of photoresist application tool 1882. A waferhandling robot 1888 can be included within the photoresist applicationtool 1882 or can be included in a separate transfer chamber which canaccess each of the individual stations of the photoresist applicationtool 1882. In an embodiment of the present invention, the wafer handler1888 is a single wafer handling robot on a single linear track. In anembodiment of the present invention, robot 1888 can take a wafer fromphotoresist application module 1882 and insert it directly into backsidecleaning tool 1884.

Backside cleaning tool 1884 can be any suitable apparatus which canclean and remove particles from the backside of a wafer without exposingthe frontside of the wafer, on which a photoresist film is formed, tocleaning or wetting solutions. In an embodiment of the presentinvention, the backside cleaning tool 1884 can be a single wafer wetclean module, such as module 200, shown in FIG. 2A-2C. Other types ofcleaning apparatuses, however, can be used as long as they can clean thebackside of the wafer without affecting the frontside and a photoresistfilm formed thereon. For example, backside cleaning tool can include awafer support for holding or rotating a wafer above a rotatable brushwhich is used for dislodged particles from the wafer backside. Inanother embodiment of the present invention, the backside cleaning toolcan include an air knife which utilizes air flow to create an air shearto remove particles from the wafer backside while the wafer is rotated.

Exposure tool 1886 can be any well-known exposure tool, such as astepper, where photoresist material is exposed to radiation, such asdeep ultraviolet (DUV) radiation or extreme ultraviolet (EUV) radiationthrough a mask used to define a pattern within the photoresist film.Exposure tool 1886 contains a wafer handling device 1890, such as arobot, which is able to receive a wafer from backside cleaning tool 1884and position the wafer within exposure tool 1886. Robot 1890 can alsoremove the wafers from exposure tool 1886.

In a method of use of apparatus 1880, a wafer, such as wafer 1900 asshown in FIG. 19A is placed into photoresist application tool 1882 wherea photoresist film 1910 is formed on the wafer frontside 1902. Ideally,wafer 1900 has been sufficiently cleaned prior to placing intophotoresist application tool 1882. Photoresist film 1910 can be formedby any well-known technique or series of steps, such as illustratedabove. In an embodiment of the present invention, photoresist film 1900is formed utilizing a pre-bake step such as set forth in FIG. 19C andaccompanying description, a photoresist spin step such as set forth inFIG. 19D and accompanying description, and a soft bake step as set forthin FIG. 19F and accompanying description. Robot 1888 moves a wafer 1900between the various stations of the photoresist application tool 1882.

Once a suitable photoresist film 1910 has been formed on the frontside1902 of wafer 1900, robot 1888 transfers wafer 1900 from the photoresistapplication tool 1882 to the backside clean module 1884 where thebackside 1904 of wafer 1900 is cleaned of particles. In an embodiment ofthe present invention, the backside clean occurs after the photoresistfilm 1910 has been formed and after all necessary processes haveoccurred which are necessary prior to the exposure of the photoresist1910. In an embodiment of the present invention, the backside cleanoccurs directly after a soft bake step such as shown in FIG. 19F. In anembodiment of the present invention, the backside cleaning occursdirectly before or immediately before placement in exposure tool 1886and exposure therein. In an embodiment of the present invention, thebackside cleaning occurs in a single wafer wet cleaning module 200 shownin FIG. 2A-2C. In such a case, the wafer 1900 having a photoresist film1910 formed on the wafer frontside 1902 is then held by wafer support210 horizontally above and parallel to plate 202 as shown in FIG. 2A.Wafer backside 1904 is adjacent to plate 202. A fluid such as DI wateror a cleaning solution comprising, for example ammonia/peroxide/water,is then transported between plate 202 and wafer backside 1904 in orderto remove particles 1908 which develop during the photoresist formationprocess. The cleaning solution can include a chelating agent and/orsurfactants. While the liquid is flowing between the backside of thewafer 1904 and plate 202, megasonic energy is applied by transducers 204to produce sonic waves in a direction perpendicular to the backside ofthe wafer 1900. The wafer can be rotated by support 210 while cleaningthe backside. During backside cleaning of the wafer with photoresistmaterials 1910 on the frontside, no solution is provided through nozzle214 to the wafer frontside 1902. That is, during the backside clean thephotoresist film on the frontside is kept completely dry. It is to beappreciated that the photoresist film 1910 formed on the wafer frontsideis not to be exposed to cleaning solution or DI water during the waferbackside cleaning. In an embodiment of the present invention clean airor an inert gas, such as N₂, can be blown onto a top surface of wafer1900 while the backside 1904 is cleaned to insure that no backsidecleaning solution travels around the edges of the wafer and wets orattacks the photoresist film 1910 on the wafer frontside 1902. The inertgas can be blown onto the wafer frontside through nozzle 214 or aseparate nozzle can be provided.

After the backside of wafer 1900 has been sufficiently cleaned, thewafer 1900 is removed from the backside cleaning chamber 1884 by robot1890 and is placed into exposure tool 1886. In exposure tool 1886, thephotoresist film 1910 is exposed to radiation, such as DUV radiationfrom a light source 1940 which shines through a mask 1916 having apattern formed therein as shown in FIG. 19G. The light radiation altersthe chemical structure of the photoresist film to form light exposedregions 1920 which can be selectively developed away with a developerfrom photoresist film 1910 which has not been exposed to light (1918). Ahigh quality exposure can take place because backside particles havebeen removed which could otherwise cause the image to be out of focus.Thus, a high quality photolithography processing apparatus and methodhave been described.

FIG. 18D illustrates another embodiment of a photolithography processingapparatus. Photolithography processing apparatus 1892 includes aphotoresist application tool or track 1882 as described above, a bufferstation 1894 and an exposure tool 1886 as described above. Bufferstation 1894 is located between photoresist application tool 1882 andexposure tool 1886. Buffer station 1894 includes a transfer chamber 1896which has one side directly coupled to the output of a photoresistapplication tool 1886 and a second side which is directly coupled to theinput of exposure tool 1886. Buffer station 1894 also includes abackside cleaning tool 1884, as described above, which is directlycoupled to transfer chamber 1896 on a third side. In an embodiment ofthe present invention, buffer tool 1894 includes a backside integratedparticle monitoring tool 1894 for inspecting the wafer backside forparticles. In an embodiment of the present invention, backsideintegrated particle monitoring tool can include a light emitter forshining light onto the backside of the wafer and collectors or detectorsfor collecting the light scattered from the wafer backside to inspectthe wafer backside for particles. An example of suitable backsideparticle monitoring tool is IPM tool 300 shown in FIG. 3. IMP Tool 300,however, would be configured to scan the wafer backside as opposed tothe frontside as shown in FIG. 3. Transfer chamber 1896 has a waferhandling robot 1899 contained therein for handling a single wafer. Waferhandling robot 1899 can receive a wafer from robot 1888, of photoresistapplication tool 1882 and robot 1899 can provide a wafer to robot 1890of exposure tool 1886. Additionally, robot 1899 can transfer a waferinto backside cleaning tool 1884 and into backside particle monitoringtool 1897, if used.

In a method of use, of photolithography apparatus 1892 shown in FIG.18D, a wafer is placed into photoresist application tool 1882 where ittravels down the track and enters the various process stations used toform a photoresist film on the wafer and to prepare the photoresist filmfor exposure in tool 1886. Once a suitable photoresist film has beenformed on the wafer frontside, the wafer is transferred by robot 1888 torobot 1899 where it is brought into transfer chamber 1896. In anembodiment of the present invention, robot 1899 transfers the wafer intobackside cleaning tool 1884 where the wafer backside is cleaned ofparticles as discussed above. After a sufficient backside cleaning, thewafer is removed from backside cleaning chamber 1884 by robot 1899 andbrought back into transfer chamber 1896. In an embodiment of the presentinvention, where a backside particle monitoring tool 1897 is provided,after backside cleaning the wafer, the wafer can be transferred by robot1899 into backside integrated particle monitoring tool 1897 where itsbackside is inspected for particles. If the backside is suitably clean,the wafer can be removed by robot 1899 from backside particle monitoringtool 1897 and brought into transfer chamber 1896. Robot 1899 thentransfers the wafer to the robot 1890 of exposure tool 1886 whichpositions the wafer for exposure as described above. In an embodiment ofthe present invention, if the backside particle monitoring tooldetermines that the backside is not sufficiently cleaned, the wafer canbe transferred back into backside cleaning module 1884 for additionalbackside cleaning. After additional backside cleaning, the wafer can betransferred back into backside particle monitoring tool 1897 andreinspected for particles.

In yet another embodiment of the present invention, after thephotoresist film has been formed and prepared in photoresist applicationtool 1882, the wafer can be first transferred into backside inspectiontool 1894 to inspect for particles and then the wafer transferred intobackside cleaning tool 1884. In this way, information regarding thebackside particles can be used to determine the type and amount ofbackside cleaning in backside cleaning chamber 1884. After a sufficientbackside cleaning in backside cleaning apparatus 1884 the wafer can betransferred back into backside particle monitoring tool 1897 and thewafer reinspected prior to transferring the wafer into exposure tool1886. Thus, a high quality photolithographic processing apparatus hasbeen described as well as its method of operation.

Computer/Controller

FIG. 20A illustrates a computer/controller 124 which can be used tocontrol the movement and processing of a wafer in a tool, such as tool100, 600, 1200 and 1800 in accordance with the present invention.Computer/controller 124 includes a memory 740, such as a hard drive orother type of memory, a processor 720 and an input/output device, suchas a CRT Monitor 730 and a keyboard 732. The input/output device is usedto interface between a user and computer/controller 124. Processor 720executes a system control software program stored in computer readablemedium, such as memory 740. Processor 720 executes the system controlsoftware and provides and receives control signals for the tool whichcontrols the transfer of wafers through the tool and which provides thespecific control signals necessary to achieve the specific processingparameters for each of the modules coupled to the tool, such as processtemperature, process gas/fluid flows and process pressure, etc.

The process for processing a wafer in accordance with the embodiment ofthe present invention can be implemented using a computer programproduct which is stored in memory 740 and is executed by processor 720.The computer program code can be written in any conventional computerreadable program language, such as 68000 Assembly Language, C, C++,Pascal, Fortran, or others. Suitable program code is entered into asingle file or multiple files using conventional text editor and storedor embodied in a computer usable medium, such as a memory system of thecomputer. If the entered code text is in the high level language, a codeis compiled and the resultant compiler code is then linked with anobject code of precompiled windows library routines. To execute the linkcompiled object code, the system user invokes the object code causingthe computer system to load the code in memory from which the processorreads and executes the code to perform the task identified in theprogram. Also stored in memory 740 are process parameters, such asprocess gas/fluid flow rates and composition, temperatures, pressures,and times necessary to carry out the deposition of films, the etching offilms, the wet cleaning of wafers, the ashing of wafers, as well as themonitoring and recording of metrology of the wafer, such as filmthickness uniformity and defects.

FIG. 20B illustrates an example of the hierarchy of the system controlcomputer program stored in memory 740. The system control programincludes a tool manager subroutine 2000. The tool manager subroutine2000 also controls the execution of various chamber componentsubroutines which control the operation of the chamber componentsnecessary to carry out the selected process set in the various chambersor modules of the tool. Examples of chamber component subroutines areprocess gas/fluid control subroutine 2002, pressure control subroutine2004, temperature control subroutine 2008, and a wafer supportsubroutine 2010. Additionally, the tool manager subroutine includes awafer history subroutine 2012 and a wafer transfer subroutine 2014.Those having ordinary skill in the art would readily recognize thatother chamber control subroutines can be included depending on whatprocesses are desired to be performed in the tool and process modules.In operation, the tool manager subroutine 2000 selectively schedules orcalls a process component subroutines in accordance with the particularprocess set being executed. Typically, the tool manager subroutine 2000includes steps of monitoring the various chamber components, determiningwhich components need to be operated based on the process parameters ofthe process set to be executed and causing execution of a chambercomponent subroutine responsive to the monitoring and determining step.

The process gas/fluid control subroutine 2002 has a program code forcontrolling the reactive gas/fluid composition and flow rates. Theprocess gas/fluid control subroutine 2002 controls the open/closeposition of the safety shut off valves, and also ramps up and down themass flow controllers to obtain the desired gas/fluid flow rates. Theprocess gas/fluid control subroutine 2002 is invoked by the tool managersubroutine 2000 as are all chamber component subroutines and receivesfrom the tool manager subroutine process parameters related to thedesired gas/fluid flow rates. Typically, the process gas/fluid controlsubroutine 2002 operates by opening the gas supply lines and repeatedly(i) reading the necessary mass flow controllers, (ii) comparing thereadings to the desired flow rates received from the tool managersubroutine 2000 and (iii) adjusting the flow rates of the gas/fluidsupply lines as necessary. Furthermore, the process gas/fluid controlsubroutines 2002 includes steps for monitoring the gas/fluid flow ratesfor unsafe rates, activating safety shut off valves when unsafeconditions is detected.

The process control subroutine 2004 comprises program code forcontrolling the pressure in the chamber of the various modules, as wellas the pressure within the sub-atmospheric transfer chamber and loadlocks by regulating the size of the opening of the throttle valves whichare set to control the chamber pressure to the desired level in relationto the total process gas flow, size of the process chamber, and pumpingset point pressure for the exhaust system. When the pressure controlssubroutine 2004 operates to measure the pressure in a chamber by readingone or more conventional pressure manometers connected to the chamber,compared to measure values to the target pressure and adjust thethrottle valve according to the PID values obtained from the pressuretable. Alternatively, the pressure control subroutine 2004 can bewritten to open or close the throttle valve to a particular opening sizeto regulate the chamber to a desired pressure.

The temperature control subroutine 2008 comprises program code forcontrolling the power provided to heaters or lamps which are used toheat the substrate or wafer. The temperature control subroutine 2008 isalso invoked by the chamber manager subroutine 2000 and receives atarget or set point temperature parameter. The temperature controlsubroutine 2008 measures the temperature by measuring voltage output ofa temperature measurement device directed at the susceptor or wafer andcompares the measured temperature to the set point temperature, andincreases or decreases power applied to the heater or lamps to obtainthe set point temperature.

The wafer support subroutine 2010 has a program code for controlling thepositioning and rotation rates of a wafer support members, such assusceptors, during the processing of wafers and during the loading andunloading of wafers into the module or chamber. The wafer supportsubroutine controls the motors which control the height position of thewafer support and the motors which control the rotation rates of thewafer support.

The wafer history subroutine 2012 has program code for storing andretrieving as well as analyzing the process history of a wafer in thetool. Wafer history subroutine 2012 store data detailing the processesthat have occurred to a wafer processing in the tool as well asmetrology information on each wafer, such as film thickness anduniformity maps as well as defect maps.

The wafer transfer subroutine 2014 comprises program code forcontrolling the transfer of a wafer throughout the tool. Wafer transfersubroutine 2014 determines which chamber or modules of the tool a waferis to be processed in as well as the order of the processing. Wafertransfer subroutine 2014 can utilize information from the wafer historysubroutine to determine which processes a wafer is to experience. Forexample, after a metrology scan to determine the number or type ofparticles on a wafer, the wafer transfer subroutine can be invoked todetermine whether or not the wafer should be further wet cleaned orashed or be sent to the next module in the process. The wafer subroutinecan utilize wafer metrology information to determine the subsequentprocessing of the wafer.

Thus, novel atmospheric/sub-atmospheric process tools and their methodsof use have been described.

1. A method of cleaning a residue or a photoresist layer from a wafercomprising: transferring from a wafer cassette a wafer having a residuethereon into a transfer chamber having robot contained therein;transferring said wafer from said transfer chamber into an ashing modulecoupled to said transfer chamber; ashing said wafer in said ashingmodule to form an ashed wafer; transferring said ashed wafer from saidashing module to said transfer chamber; transferring said ashed waferfrom said transfer chamber to a wet processing module coupled to saidtransfer chamber; cleaning said ashed wafer with a cleaning solution insaid wet processing chamber to form a cleaned and ashed wafer;transferring said cleaned and ashed wafer from said cleaning module tosaid transfer chamber; and removing said cleaned and ashed wafer fromsaid transfer chamber.
 2. The method of claim 1 wherein said ashingcomprises: exposing said wafer to an energized cleaning gas; and before,during or after exposing said wafer to said energized cleaning glass,exposing the said wafer to an energized treating gas comprising ahalogen species and a hydrogen species.
 3. The method of claim 2 whereinthe cleaning gas comprises: a stripping gas comprising one or more OfO₂, N₂, H₂O, NH₃, CF₄, C₂F₆, CHF₃, C₃H₂F₆, C₂H₄F₂, and CH₃F providedunder process conditions selected to at least partially remove saidresidue when said residue is remnant resist material.
 4. The method ofclaim 1 wherein said cleaning comprises: transmitting sonic energy to anon-device side of said wafer while flowing said cleaning solution ontosaid wafer device side.
 5. The method of claim 2 wherein said cleaningcomprises: transmitting sonic energy to a non-device side of said waferwhile flowing said cleaning solution onto said wafer device side.
 6. Amethod of processing a wafer comprising: transferring a wafer from awafer cassette into an atmospheric transfer chamber; transferring saidwafer from said atmospheric transfer chamber into a load lock coupled tosaid atmospheric transfer chamber; reducing the pressure in said loadlock to a sub-atmospheric pressure; transferring said wafer from saidload lock into a sub-atmospheric transfer chamber coupled to said loadlock; transferring said wafer from said sub-atmospheric transfer chamberinto a sub-atmospheric process chamber coupled to said sub-atmospherictransfer chamber; processing said wafer in said sub-atmospheric processchamber to produce a sub-atmospheric processed wafer; transferring saidsub-atmospheric processed wafer from said sub-atmospheric processchamber to said sub-atmospheric transfer chamber; transferring saidsub-atmospheric processed wafer from said sub-atmospheric transferchamber into a load lock at said sub-atmospheric pressure; raising thepressure in said load lock to atmospheric pressure; transferring saidsub-atmospheric processed wafer from said load lock to said atmospherictransfer chamber; transferring said sub-atmospheric processed wafer fromsaid atmospheric transfer chamber to an atmospheric process chambercoupled to said atmospheric transfer chamber; processing saidsub-atmospheric processed wafer in said atmospheric process chamber toproduce a sub-atmospheric processed and a atmospheric processed wafer;transferring said sub-atmospheric processed and said atmosphericprocessed wafer from said atmospheric processing chamber to saidatmospheric transfer chamber; and removing said sub-atmosphericprocessed and said atmospheric processed wafer from said atmospherictransfer chamber.
 7. The apparatus of claim 6 further comprising a CDmeasurement tool coupled said sub-atmospheric transfer chamber.
 8. Amethod of processing a wafer comprising: transferring a wafer having apatterned photoresist layer formed on a thin film from a wafer cassetteinto an atmospheric transfer chamber; transferring said wafer from saidatmospheric transfer chamber into a load lock coupled to saidatmospheric transfer chamber; reducing the pressure in said load lock toa sub-atmospheric pressure; transferring said wafer from said load lockinto a sub-atmospheric transfer chamber coupled to said load lock;transferring said wafer from said sub-atmospheric transfer chamber intoan etch chamber coupled to said sub-atmospheric transfer chamber;etching said thin film in alignment with said patterned photoresistlayer in said etch chamber at a sub-atmospheric pressure to form anetched wafer; transferring said etched wafer from said etch chamber tosaid sub-atmospheric transfer chamber; transferring said etched waferfrom said sub-atmospheric transfer chamber to an ashing chamber coupledto said sub-atmospheric transfer chamber; ashing said etched wafer insaid ashing chamber to remove said patterned photoresist layer;transferring said etched and ashed wafer from said ashing chamber tosaid sub-atmospheric transfer chamber; transferring said etched andashed wafer from said sub-atmospheric transfer chamber into a load lockat said sub-atmospheric pressure; raising the pressure in said load lockto atmospheric pressure; transferring said etched and ashed wafer fromsaid load lock to said atmospheric transfer chamber; transferring saidetched and ashed wafer from said atmospheric transfer chamber to a wetcleaning chamber coupled to said atmospheric transfer chamber; cleaningsaid etched and ashed wafer in said wet cleaning chamber to produce anetched, ashed, and cleaned wafer; transferring said etched, ashed, andcleaned wafer from said wet cleaning chamber to said atmospherictransfer chamber; and removing said etched, ashed, and cleaned processedwafer from said atmospheric transfer chamber.
 9. The method of claim 8wherein said thin film comprises a metal film.
 10. The method of claim 8wherein said thin film comprises a stack of metal films.
 11. The methodof claim 10 wherein said stacked metal film comprises an anti-reflectivelayer, a main conductive layer, and a barrier layer.
 12. The method ofclaim 8 wherein said thin film is a dielectric film.
 13. The method ofclaim 12 wherein said dielectric film is selected from the groupconsisting of silicon dioxide, silicon oxynitride, SiOF, BPSG, undopedsilicon pass and organic dielectrics.
 14. The method of claim 8 whereinsaid ashing comprises: exposing said wafer to an energized cleaning gas;and before, during or after exposing said wafer to said energizedcleaning gas, exposing said wafer to an energized treating gascomprising a halogen species and a hydrogen species.
 15. The method ofclaim 14 wherein said cleaning gas comprises: a stripping gas comprisingone or more of O2, N2, H2O, NH3, CF4, C2F6, CHF3, C3H2F6, C2H4F2, andCHF3 provided under pressure conditions selected to at least partiallyremove said residue when said residue is remnant resist material. 16.The method of claim 8 wherein said cleaning comprises: transmittingsonic energy to a nondevice side of said wafer while flowing saidcleaning solution on said wafer device side.
 17. The method of claim 8wherein said cleaning comprises: transmitting sonic energy to anondevice side of said wafer while flowing said cleaning solution ontosaid device side.
 18. The method of claim 8 further comprising: prior totransferring said wafer from said atmospheric transfer chamber into saidload lock, transferring said wafer into a CD measurement tool, anddetermining whether or not the CD measurements are in compliance. 19.The method of claim 18 wherein if said CD measurements are not incompliance transferring said wafer into a ashing chamber coupled to saidatmospheric transfer chamber, and removing said photoresist mask in saidashing chamber.
 20. The method of claim 8 further comprising the stepof: prior to etching said thin film in said etch chamber, trimming saidphotoresist mask.
 21. The method of claim 20 wherein said trim utilizesoxygen plasma.
 22. The method of claim 8 wherein after ashing saidwafer, passivating said substrate to a passivating gas which inactivatescorrosive etchant residue.
 23. The method of claim 8 further comprisingthe step of: after ashing said wafer in said ashing chamber,transferring said wafer from said atmospheric transfer chamber into a CDmeasurement tool, and checking the critical dimensions of said etchedwafer.
 24. The method of claim 8 wherein after wet cleaning said etchedand ashed wafer transferring said etched, ashed and cleaned wafer into acritical dimension monitoring tool coupled to said atmospheric transferchamber and checking said critical dimensions of said etched film. 25.The method of claim 8 wherein said thin film is a dielectric film, andfurther comprising after transferring said etched, ashed and cleanedwafer from said wet cleaning chamber to said atmospheric transferchamber; transferring said etched, ashed and cleaned wafer from saidatmospheric transfer chamber into a load lock coupled to saidatmospheric transfer chamber; reducing the pressure of said load lock toa sub-atmospheric pressure; transferring said wafer from said load lockinto a sub-atmospheric transfer chamber coupled to said load lock;transferring said wafer from said sub-atmospheric transfer chamber intoa metal deposition chamber coupled to said sub-atmospheric transferchamber; depositing a metal film in said deposition chamber coupled tosaid sub-atmospheric transfer chamber.
 26. A method of forming atransistor comprising: transferring a monocrystalline silicon substratefrom a wafer cassette into an atmospheric transfer chamber; transferringsaid a monocrystalline silicon substrate from said atmospheric transferchamber to a wet cleaning chamber coupled to said atmospheric transferchamber; cleaning said monocrystalline silicon substrate with a cleaningsolution in said cleaning apparatus; transferring said cleanedmonocrystalline silicon substrate from said cleaning chamber to saidatmospheric process chamber; transferring said a monocrystalline siliconsubstrate from said atmospheric transfer chamber into a load lockcoupled to said atmospheric transfer chamber; reducing the pressure insaid load lock to a sub-atmospheric pressure; transferring said amonocrystalline silicon substrate from said load lock into asub-atmospheric transfer chamber coupled to said load lock; transferringsaid wafer from said sub-atmospheric transfer chamber into an oxidationchamber coupled to said sub-atmospheric transfer chamber; oxidizing themonocrystalline silicon substrate to a monocrystalline silicon substrateto form a dielectric film on said monocrystalline silicon substrate insaid oxidation chamber; transferring said oxidized monocrystallinesilicon substrate from said oxidation chamber to said sub-atmospherictransfer chamber; transferring said oxidized wafer from sub-atmospherictransfer chamber to a polysilicon deposition chamber coupled to saidsub-atmospheric chamber; depositing a polysilicon film on saiddielectric film formed on said monocrystalline silicon substrate in saidpolysilicon deposition chamber; transferring said wafer with saiddeposited polysilicon film from said polysilicon deposition chamber tosaid sub-atmospheric transfer chamber; transferring said oxidized andpolysilicon deposited wafer from said sub-atmospheric transfer chamberinto a load lock at said sub-atmospheric pressure; raising said pressurein said load lock to atmospheric pressure; transferring said oxidizedand polysilicon deposited wafer from said load lock to said atmospherictransfer chamber; and removing said oxidized and polysilicon depositedwafer from said atmospheric transfer chamber.
 27. A method of strippinga silicon nitride film from a wafer comprising: transferring a waferhaving a silicon nitride film thereon into an atmospheric transferchamber; transferring said wafer from said atmospheric transfer chamberinto a load lock coupled to said atmospheric transfer chamber; reducingthe pressure in said load lock to a sub-atmospheric pressure;transferring said wafer from said load lock into said sub-atmospherictransfer chamber coupled to said load lock; transferring said wafer fromsaid sub-atmospheric transfer chamber into an etch module coupled tosaid sub-atmospheric transfer chamber; etching said silicon nitride filmfrom said wafer in said etch module coupled to said sub-atmosphericprocess chamber; transferring said silicon nitride stripped wafer fromsaid etch module to said sub-atmospheric transfer chamber; transferringsaid silicon nitride etched wafer from said sub-atmospheric transferchamber into a load lock at said sub-atmospheric pressure; raising thepressure in said load lock to atmospheric pressure; transferring saidsilicon nitride etched wafer from said load lock to said atmospherictransfer chamber; transferring said silicon nitride etched wafer fromsaid atmospheric transfer chamber to a wet cleaning module coupled tosaid atmospheric transfer chamber; and cleaning said silicon nitrideetched wafer in said wet cleaning chamber to produce a silicon nitrideetched and cleaned wafer.
 28. The method of claim 27 wherein said wetcleaning comprises: transmitting sonic energy to a nondevice side ofsaid wafer while flowing a solution on said wafer device side.
 29. Themethod of claim 27 further comprising after cleaning said wafer in saidwet cleaning module, transferring said wafer to a particle monitoringtool coupled to said atmospheric transfer chamber, and checking saidsurface of said wafer for particles or residue.
 30. The method of claim29 further comprising utilizing said information from said particlemonitoring tool to alter the silicon nitride strip parameters and/or thewet cleaning parameters for processing of subsequent wafers.
 31. Amethod of photolithographic processing of a wafer comprising: forming aphotoresist film on a first side of a wafer having said first side and asecond side opposite said first side; cleaning said wafer second sidewith a solution while said photoresist is on said wafer first side; andexposing said photoresist film on said wafer first side to radiationafter cleaning said wafer second side with said solution.
 32. The methodof claim 31 wherein said cleaning of said wafer second side comprises:horizontally positioning said wafer second side adjacent to andspaced-apart from a horizontal plate; and providing said solutionbetween said plate and said wafer second side.
 33. The method of claim32 further comprising applying acoustic energy to a second side of saidplate while flowing said fluid between said plate and said wafer secondside.
 34. The method of claim 33 wherein said acoustic energy is appliedin a direction normal to said wafer second side.
 35. The method of claim34 wherein said acoustic energy is applied at a frequency ofapproximately 925 KHz.
 36. The method of claim 31 wherein said waferfrontside is kept dry while cleaning said wafer backside.
 37. The methodof claim 31 wherein said wafer first side has a plurality of patternsformed thereon.
 38. A method of photolithographically processing a wafercomprising: placing a wafer into a transfer chamber; transferring saidwafer from said transfer chamber into a single wafer wet clean moduledirectly coupled to said transfer chamber; cleaning said wafer backsidein said single wafer cleaning module to produce a backside cleanedwafer; transferring said backside cleaned wafer from said single waferclean module to said transfer chamber; transferring said backsidecleaned wafer from said transfer chamber to a photoresist applicationmodule directly coupled to said transfer chamber; applying photoresistto said wafer front side opposite said backside in said photoresistapplication module to produce a photoresist deposited wafer;transferring said photoresist deposited wafer from said photoresistapplication module to said transfer chamber; transferring saidphotoresist deposited wafer from said transfer chamber to an exposurestation coupled directly to said transfer station; and exposing saidphotoresist on said photoresist deposited wafer to radiation to producea radiation exposed photoresist film on said photoresist depositedwafer.
 39. The method of claim 38 wherein said cleaning of said waferbackside comprises: horizontally positioning said wafer backsideadjacent to and spaced-apart from a horizontal plate; and flowing afluid between said horizontal plate and said wafer backside.
 40. Themethod of claim 39 further comprising applying acoustic energy to asecond side of said horizontal plate while flowing said fluid betweensaid plate and said wafer backside.
 41. The method of claim 40 whereinsaid acoustic energy is applied in a direction normal to said waferbackside.
 42. The method of claim 41 wherein said wafer frontside iskept dry while cleaning said wafer backside.
 43. The method of claim 41further comprising: cleaning said wafer frontside by flowing a secondfluid onto said wafer front side while providing said fluid between saidplate and said wafer second side.
 44. The method of claim 39 furthercomprising filtering amine and ammonia vapors from said transferchamber.
 45. A method of photolithographically processing a wafercomprising: placing a wafer having a frontside opposite a backside intoa photoresist application tool and forming a photoresist film on saidfrontside of said wafer; removing said wafer from said photoresistapplication tool and placing said wafer into a backside cleaning tooland cleaning the backside of said wafer without exposing the waferfrontside to cleaning solutions or chemicals; and removing said waferfrom said backside cleaning tool and placing said wafer into a exposuretool and exposing said photoresist film to radiation in said exposuretool.
 46. The method of claim 45 when the step of forming saidphotoresist film on said wafer frontside includes baking said wafer toremove moisture from said wafer, and spinning a photoresist film on saidwafer, and heating said wafer to remove solvents contained within saidphotoresist film.
 47. The method of claim 45 wherein said cleaning ofsaid wafer backside comprises: horizontally positioning said waferbackside adjacent to and spaced-apart from a horizontal plate; andflowing a fluid between said horizontal plate and said wafer backside.48. The method of claim 47 further comprising applying acoustic energyto a second side of said horizontal plate while flowing said fluidbetween said plate and said wafer backside.
 49. The method of claim 48wherein said acoustic energy is applied in a direction normal to saidwafer backside.
 50. The method of claim 45 further comprising aftercleaning the backside of said wafer, placing said wafer in a backsideparticle inspection tool and inspecting said wafer backside forparticles.